I have to admit that I'm a much much better listener than player, so I do fit well in the 'audience' category.

Why I play?
Simply because I love to play, specially if I feel I manage to make it sound like music.
Also because it make me relax and stress down from everything else around me.

Some years ago, when gig as duo or trio, I also learned that it gave a lot of joy (and some income) to entertain others.
But nowadays, it's mostly for my own pleasure. It's a lovely hobby.