This revealed itself as I was working on a game engine reimplementation. For two years I was personally satisfied with myself by being able to return to a hobby and actively enjoy my time programming, and I thought I had managed to find something I was comfortable with doing just for myself.
It turned out that I was deceiving myself by saying that I was in it for the personal enjoyment. This was false. I was ultimately working towards a goal that I didn't properly define, which was releasing the engine. This is the goal that everyone talks about when discussing game development, and it is a goal that carries value only because it involves other people - people that learn about and play your game.
So in the future I will have to be more perceptive of the goals I'm hesitant to admit exist. From the beginning, I was only ever going to work on such a project with the eventual goal of making a release, as in making my project have an effect on people other than myself. That meant I was only working on my project for other people, and not for myself. The enjoyment I found in working on it was nothing more than a prerequisite to getting to work. It makes you feel virtuous to think otherwise, but it's nothing more than an elaborate lie.
I don't understand how one could possibly develop games just for their own sake if shipping the finished game to other people is the point of game development.
I guess I would say that if you aren't willing to permanently delete everything that you've worked on the moment you've finished a project, then you're not actually "doing it for yourself". That isn't necessarily a bad thing, but you have to be honest or perceptive enough to be able to admit the truth.