I don't really give a damn any more, honestly. I'm tired of waiting for people to say things so I tend to start conversations when I want, or be silent when I want to. I seem to mostly know a lot of introverted people (?), so I tend to just start things up anyways. It baffles me that people sometimes "wait" for other people to bring things up.
The only time I tend to be quiet is if there are a lot of weird social things going on or raucousness that seems pointless or destructive or foolish - sometimes that's because it actually is, or because I haven't been acclimated to it yet.
I tend to gravitate towards people and discussions and arenas I personally like or enjoy - there are plenty of losers and uninteresting things out there, best not to put energy into those things unless it's important . . .