There is no expectation or obligation to ever become more. It is just for fun, learning, and curiousity. I can add whatever features I want. I can use whatever technologies I want. I can throw it all away if I want. These are the projects I yearn for and look forward to when I'm busy with work.
Perhaps George Bernard Shaw was on to something: "We don't stop playing because we grow old; we grow old because we stop playing."
Funny enough, Titus Barik published a paper that contributes a qualitative analysis on the sentiment of programming and play on Hacker News. The themes he found include play as artistry, catalyst, fun, playgrounds, spontaneity, tinkering, and anti-work. There is a quote that I particularly like, "The joy of programming for programming's sake is something you do in your own time."
It all makes sense to me, because I have spent a lot of time building useless stuff. Mostly compilers and game engines. To name a few projects: