I'm a writer. When I write, I try to avoid things that have already been done for precisely that reason. I would hate to show somebody something that wasn't new and stimulating for THEM.
For me, a part of the fun of making art is creating things that other people truly, honestly enjoy. I think the same would occur with programming.
I definitely agree that creating something that other people enjoy is the most rewarding.
I'm not a writer, so I don't presume to tell you about your own craft, but there might be a difference between writing and programming/painting: I can definitely enjoy programs I've written (not reading my own source code, but actually using the programs), and if I were more talented, I could see myself enjoying looking at my own paintings, but I find it hard to see myself reading my own writings for enjoyment. Perhaps making something that other people enjoy is more necessary for a writer than for a programmer or painter?
For me, a part of the fun of making art is creating things that other people truly, honestly enjoy. I think the same would occur with programming.