Yes... It's therapy. If I stop now, I'm not really sure what would happen.

Although jamming with a band, getting constructive critiques, hammering out a complex part, talking shop about the process, etc... that's where a lot of the fun can be found. I'd still make it without all that, but it would be a sadder/meaner sounding bunch of crap, instead of just a selfish, not-for-mass-consumption-type bunch of crap.