I'm so much of a hoarder that even after I've decided I want my game to behave in a completely different way, and I have no need for entire pages of code... rather than erase it, I comment it out because "I spent a lot of time on that, and maybe I'll need it later".
So my crap is full of commented out code.
and I can hear you cringing. I can hear the people in the back going "Uh... version control? Backups? Save to a different file?"
To those people I would reply simply that I am an idiot and do none of those things.
(Am going to start doing these things)