My monitors show colors differently.
My phone's brightness changes, depending on the lighting.
The angle at which I'm looking at the screen affects the color.
My room's lighting differs throughout the day.
I'm sure I see colors differently right after waking up.
I'm sure I see colors differently after I've been working for a while.
I'm not sure we all see colors the same way (Is my red the same as your red?).
Some people are color-blind (and for them, I'm contrast-blind).
How do people even work with colors?