I've been taking piano lessons this year. It's one of the skills I always wished I had. Also, I used to plink around on the piano all through high school and college writing music. I miss it, but this time I'm going to learn to play correctly in the hopes that I can write something more than just chords and a melody.
Anyway, I have run across one of the great joys of adulthood. When I was a kid, I always felt bad about not practicing enough (well, not bad enough to actually practice). As I got older, I got to see that the kids that practiced a lot were significantly better musicians, so I practiced maybe a little more than when I first started - but still not really "enough". Now that I'm an adult, I realize that I don't have to feel bad when I don't practice! It's my responsibility! No teacher is going to give me a bad grade, no parent is going to scowl, my instructor doesn't even really get that upset (I think because he has other clients that almost never practice). What's the result of my not practicing? I'm not as good at doing the thing that I chose to do.
Most of the time, I practice every day and enjoy it. However, there are times when I don't practice because I've been too busy or travelling. I relish the freedom I feel at knowing that there's no one around to admonish me. It's one of the times that I can suddenly appreciate being a responsible adult. And sure enough, I get back to practicing when my schedule frees up.