What made me join a guild. Good question.
I retired after working in IT for 20 years, moved to SC. I knew no one, spent my first 2.5 years here intentionally being a hermit. It took me that long to unwind from the 20 years of days so long and filled with work, then home to family, then back to work. Don't get me wrong on this, I love my family very much and regret nothing, and I actually was one of the lucky few who loved my job - if I had been able to work 40 - 50 hour weeks instead of the 60 - 80 hour weeks that I put in, I'd probably still be working. I was burned out and just needed a long break.
It was such a pleasure to have no commitments to anyone - exception for grandchildren, of course - I couldn't even commit myself to going grocery shopping until it was a dire necessity!
Then, as happens, I decided that I had to be a grown up again. So I joined 2 guilds and started doing volunteer work once a week. The guilds are very different. One is small and more socially oriented, the other is larger and has a personality somewhat like mine - a bunch of slightly driven people who organize the talent and get lots of lessons and projects done, lots of charity and QOV quilts.
It took me a while to feel really comfortable in the guilds, but that wasn't because the members of the guilds were snooty or "cliqued up". It just takes ME a while to warm up in new situations.
The only thing that would make me quit either of the guilds - won't know until it happens.