I brew for obvious reasons:
1) I like beer
2) My friends like beer
3) I like the variety brewing allows. And that if I don't like something, I can change it.
I also brew for reasons that a bit more complex:
1) Brewing a batch has a defined start and end. I know when I'm done and that gives a sense of closure. My j-o-b in the IT department of a large bank doesn't really offer anything in the way of feeling like you finished something. Most work we do either goes on forever with new releases and the HW/OS upgrade treadmill or the funding gets cut and everything just stops. Most projects end long before anyone really says they're done, they just kind of fade into the back.
2) Along the same lines as #1. I get real feedback from people who use my product. They like it or they don't. They don't keep coming back just because I'm the only place that, kinda, gives them what they need.
3) It gives "quiet time" where I can focus on doing one thing and no one interrupts me, unless it is really urgent. Not business "urgent" like "I changed my requirements and never told you so you didn't give me what I wanted, now fix it" urgent. Really urgent, like "Dad, the car's on fire", urgent. Just me, my radio and the brewing. All the minor stuff can wait.
I'm not really antisocial but I'm still trying. I can get there. 8^)