You are standing in the middle of the grocery store at 6:14 PM on a Tuesday. You are staring at a wall of olive oil. There are thirty seven varieties of olive oil. Some are extra virgin, some are cold pressed, some are organic, and some have labels that look like they were designed by a Tuscan poet who lives in a villa you will never afford.
You have a job. You have a family. You have a mortgage. You have a list of things you need to do before you can finally sleep. But right now, your entire cognitive capacity is being held hostage by the question of whether you should spend nine dollars or fourteen dollars on a bottle of fat.
This is not a story about olive oil. This is a story about the invisible leak in your brain that is slowly draining your ability to be a happy, functional person.
You have probably felt this sensation before. It is the feeling of standing in front of an open fridge, staring into the void, unable to decide if you want a sandwich or leftover pasta. It is the feeling of opening Netflix and scrolling for forty minutes until it is too late to actually watch a movie. It is the feeling of lying in bed at 3 AM, re-litigating a conversation you had four years ago, wondering if you should have said "You too" when the waiter told you to enjoy your meal.
We call this decision fatigue, but that name is too gentle. It sounds like a mild case of the sniffles. What is actually happening is far more violent. You are suffering from a systemic failure of your personal operating system. You are stuck in a loop of manual regression, and it is killing your spark.
The human brain is the most complex object in the known universe, yet it runs on the caloric equivalent of a dim light bulb. Because energy is scarce, the brain is obsessed with efficiency. It wants to take the things you do often and turn them into "macros" – little scripts that run in the background so the conscious part of your mind can focus on important things, like not getting hit by a bus or wondering why the neighbor bought a leaf blower at 7 AM.
When you first learned to drive, it was terrifying. You had to consciously think about the pressure of your foot on the brake, the position of the mirrors, and the precise timing of the turn signal. Your brain was redlining. Now, you can drive twenty miles on the highway while listening to a podcast about the fall of the Roman Empire and arrive at your destination with absolutely no memory of the trip. Your brain "cached" the act of driving. It turned a high-cost conscious activity into a low-cost background process.
The problem is that most of us are terrible at deciding what deserves to be a background process and what deserves our precious conscious attention.
We treat every Tuesday night dinner like a brand new, existential crisis. We treat every morning outfit choice like a high-stakes fashion gala. We treat every email response like a diplomatic cable. By doing this, we are forcing our "CPU" to calculate the same result over and over again from scratch.
In the world of software, if a programmer wrote a piece of code that calculated the square root of 144 a thousand times a second instead of just remembering that the answer is 12, they would be fired. But in our lives, we do this constantly. We re-run the same stressful mental simulations every single day. We are performing manual regression on our own lives. We are checking to see if the "system" still works by breaking it ourselves.
Think about the last time you had a recurring argument with a partner or a roommate. It usually goes like this: Person A does something annoying. Person B reacts. They argue for twenty minutes. They reach a tentative peace. Three weeks later, Person A does the exact same thing.
Why? Because you didn't fix the system. You just fixed the instance. You treated the argument like a unique event rather than a recurring bug in the code of your relationship. You didn't save the "answer" to the problem, so when the problem appeared again, you had to do all the emotional labor of solving it from the beginning.
This is the hidden cost of living without a cache. A cache is a storage location that holds onto the results of difficult work so that when you need those results again, you can just grab them instantly. It is a shortcut through time.
Software engineers understood this decades ago. They realized that the most expensive thing a computer can do is "compute." Accessing data that is already there is cheap, but calculating new data is expensive. If a computer has to look up a user’s profile picture every time they post a comment, the whole website will crawl to a halt. So, the engineers use a trick called memoization.
Funnily enough, programmers ran into this exact problem in the 1990s. They needed a way to make sure that if a function was called with the same input twice, the computer wouldn't actually do the work the second time. It would just look at its notes and say, "Oh, I remember this one. The answer is 42."
Here is literally what that looks like in Python:
from functools import lru_cache
@lru_cache(maxsize=None)
def solve_life_problem(problem_input):
# This represents a huge, exhausting mental effort
print(f"Doing the hard work of deciding: {problem_input}")
return "The Perfect Decision"
# The first time, it does the work. The second time, it's instant.
The @lru_cache line is a "decorator" that tells the program to remember the result of the function based on the input. If you ask it the same question again, it doesn't run a single line of the internal logic, it just hands you the result from its memory.
In your life, you are likely missing your @lru_cache. You are running the solve_life_problem("what_is_for_dinner") function every single evening at 6 PM. You are running the solve_life_problem("should_I_go_to_the_gym") function every morning at 6:30 AM.
Each time you run these functions, you are burning cognitive fuel. You are using up the limited supply of willpower and decision-making energy you have for the day. By the time you actually need to make a big, important decision, like how to handle a difficult project at work or how to respond to a family crisis, your tank is empty. You are stalled on the side of the road because you spent all your gas deciding between the organic and the regular kale.
The solution to this isn't "better time management" or "more willpower." Those are just ways to try and squeeze more out of a failing engine. The solution is to automate your trivial decisions through a process of Life Memoization.
The goal is to reduce the number of times you have to "calculate" an answer. You want to move as many things as possible from your conscious CPU to your background cache.
Take the "Steve Jobs T-Shirt" approach, but apply it to your own context. People often misunderstand why successful people wear the same thing every day. It isn't because they don't care about fashion. It is because they have memoized their wardrobe. They have decided that the "output" of the "what should I wear" function is always "black turtleneck and jeans." They have saved that result. Now, when they wake up, they don't have to run the code. They just fetch the result from the cache and move on to things that actually matter, like inventing the iPhone or whatever it is you do.
You can do this with almost every repetitive stressor in your life.
Consider your grocery shopping. Most people wander through the aisles, looking at things and asking themselves, "Do I need this? Do I want to make tacos this week? Maybe I should try that new pasta sauce." This is a manual regression. You are testing your entire culinary preference system from scratch in the middle of Aisle 4.
Instead, you can memoize your meals. Create a "Cache of Five." Five meals that you know how to make, that everyone in your house likes, and that use similar ingredients. On any night where you don't have a specific, high-interest desire to cook something new, you don't "decide" what to eat. You just pull from the cache. You aren't "deciding," you are "fetching."
The difference in energy expenditure is massive. Fetching is a low-energy task. Deciding is a high-energy task.
This applies to your emotional life as well. One of the most exhausting things we do is re-negotiate our boundaries.
Imagine you have a friend who always asks for favors that make you uncomfortable. Every time they ask, you go through a whole internal monologue. "Well, I want to be nice, but I'm really tired, and last time they didn't thank me, but if I say no they might be mad..."
This is a loop. You are re-running the calculation every single time.
If you memoize the boundary, you decide once: "I do not lend money to friends." Or, "I do not do work calls after 7 PM." Once the decision is made, it is moved to the cache. The next time the situation arises, you don't have to think. You don't have to weigh the pros and cons. You don't have to feel the guilt of the calculation. You just look at the cache and say, "I have a rule about that. The answer is no."
This feels cold to some people, but it is actually the ultimate form of self-kindness. By automating the trivial and the repetitive, you are preserving your humanity for the things that actually require it. You are saving your "thinking" for people, for creativity, for love, and for complex problems.
The engineers call it "DRY" – Don’t Repeat Yourself. It is a fundamental principle of good software design. If you find yourself writing the same logic in three different places, you should turn that logic into a single function and just call it when you need it.
Most of us are "WET" – We Enjoy Typing (or rather, We Every-time Think). We are repeating our mental logic in every room of our house, in every hour of our day.
How do you start building your cache? You look for the "Decision Hotspots."
Look at your last week and find the moments where you felt that specific kind of "tired" that isn't about physical exhaustion, but about mental friction. Usually, it's at transitions. Transitioning from sleep to work. Transitioning from work to home. Transitioning from "doing" to "resting."
These transitions are where we tend to perform manual regressions. We ask ourselves, "What should I do now?" And because we haven't cached an answer, we default to the highest-stimulation, lowest-effort activity, which is usually scrolling through a feed of strangers' opinions.
If you cache your transitions, you don't have to ask the question.
"When I finish work, I immediately put on my running shoes."
"When I get into bed, I immediately open my book."
"When I see an email that requires more than five minutes of thought, I immediately move it to the 'Tuesday Morning' folder."
You are creating a set of pre-calculated results for the common inputs of your life. You are moving from a state of constant "Computing" to a state of "Retrieving."
There is a beautiful side effect to this. When you stop using your brain to manage the mundane, your brain starts doing something wonderful. It starts wandering.
The great irony of our modern, hyper-connected life is that we are "thinking" more than ever, but we are having fewer thoughts. We are so busy calculating the logistics of our existence – the schedules, the oils, the outfits, the responses – that we have no bandwidth left for the kind of deep, associative thinking that leads to breakthroughs.
Creativity requires an idle CPU. It requires a brain that isn't currently bogged down in a manual regression. When you automate the trivial, you provide your mind with the silence it needs to start connecting dots it couldn't see before.
This is why people have their best ideas in the shower. You cannot bring your phone into the shower (usually). You cannot do "work" in the shower. And most importantly, your shower routine is so heavily cached that you don't have to think about it. You don't "decide" to wash your hair. You just do it. Your conscious mind is finally, for ten minutes, off the hook. It is in this state of "cached operation" that the creative "aha!" moments tend to bubble up.
Imagine if your whole life felt like that shower. Not that you are on autopilot, but that the boring parts are on autopilot, leaving your mind free to roam the halls of your own curiosity.
Of course, the danger of caching is "stale data." In engineering, if the underlying situation changes but the cache keeps giving you the old answer, you have a problem. If the website's profile picture changes, but the cache keeps showing the old one, the user gets confused.
In life, you have to "invalidate your cache" occasionally. You should periodically look at your "Cache of Five" meals and ask if you still actually like them. You should look at your clothing uniform and ask if it still fits who you are. You should look at your boundaries and see if they still serve you.
But the key is that this "cache invalidation" should be a deliberate, scheduled event. It should happen once every few months, not every thirty seconds in the middle of the grocery store. You decide once to review your life, and then you spend the rest of your time living it.
Stop treating your life like a series of brand new problems. Most of your problems are old. Most of your problems have already been solved by a version of you that was thinking more clearly than you are right now.
Trust that past version of yourself. Use the results they calculated.
When you stand in front of that wall of olive oil, don't run the "which oil is best" function. Just reach for the one you bought last time. The answer is already in the cache.
Save your energy. You're going to need it for the things that don't have an easy answer. You’re going to need it for the moments when life throws a brand-new, un-cached input at you, like a sudden loss, a new love, or a beautiful sunset that you actually have the mental space to enjoy.
Automate the trivial. Cache the routine. Stop the manual regression.
Your brain will thank you. And you might finally get out of the grocery store before 7 PM.
TL;DR:
- Decision Fatigue is a "Manual Regression": We waste enormous energy re-solving the same trivial problems every day instead of saving the answer.
- The Power of the Cache: Efficient systems (and people) "memoize" results, storing the output of hard work so they don't have to do it again.
- Automate the "Transitions": The most exhausting parts of life are the "What now?" moments; pre-decide these to save your mental CPU.
- Dry vs. Wet: Adopt the "Don't Repeat Yourself" principle. If a decision comes up every week, make a rule once and stop thinking about it.
- The Trojan Horse: You just learned how
functools.lru_cacheand memoization work in Python, proving that engineering principles are just human psychology with better syntax.
The most productive version of you isn't the one who works the hardest, but the one who has the fewest things to think about.
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