Ever been so stuck to a particular train of thought that you become tunnel-blind, unable to see the exit switch directly underneath your nose? I have been there, realized that I was in a groove I did not wish to occupy, and broke out of my box, so to speak.
This concerns games and the engines powering them... as a game maker who also wrote a game engine, I became unintentionally tied to its conventions and limitations, to the point that I could not see how to make games any other way. This meant that expanding my horizons suddenly became very difficult; it's the equivalent of digging yourself into a 100-meter hole and only realizing what happened after you are down there.
To break out, I had to force myself to think differently; playing games as well as making them led me to think like a game designer when playing, and after doing this for a while, I had one of those A-HA! moments: I saw where I had erred. Now that I know this, many more doors are now open!
(For the curious, my game engine was written in Java, using Swing GUI components, and I became incapable of making games without Swing GUI components. This meant I could not build for mobile devices, along with a host of other limitations from the engine's design. Now free of these chains, I can now do things I've always wanted to, but the engine would not let me do.)