I get along great in groups. Whenever I end up being roped into going to a party or some other kind of gathering I have a great time. I share interesting conversations with a variety of people, and from feedback I've received via third parties, others at the party have also enjoyed my company.
That said, if there's graceful way to bow out of such an invitation, I'd rather stay home. Not because I want to sit in my dark house with the curtains drawn, brooding, but because I have some many other interesting things I'd really like to be doing.
Sure, doing small talk at the party would be fun, but it would be even more fun to engage in small talk with my Spanish tutor on Skype, or read some more in that exciting SciFi novel I'm wrapped up in, or solve a new math puzzle somebody just posted on my mathematical games forum, or go out and harvest some tomatoes from the garden, or dabble for a few hours with my water colors, or write another chapter in that novel I've been working on for 15 years... The list is endless. And all of those activities just happen to be more fun than trying to impress (please/attract/get attention from/get ego validation from) other people while they try their very best to impress (please/attract/get attention from/get ego validation from) me.