On the flip side of that, I will pretty much never leave unles people are doing things counter to mechanics in a way that will essentially cause a fail, and when you explain why nicely (no snark just - this boss does x so we need to do y...and they flat ignore you and wipe the same way over again, or give you snark - yeah then I am out. I'll stay usually as long as I don't have to do something real life, as long as the people in the group are trying and at least being reasonable.I don't care if the group sucks completly but if you know it's not gonna get done with the current group being it a dps check or tank can't survive you gotta know when to call it. But what really drives me mad are control freaks that have to type in chat and tell you everything to do in a very rude manner most input is great it's the attitude and elitism that makes me drop group or player. I don't care if your good because you are very replaceable with equal or better teamates.
When I get a vote kick popup before we even got started, because someone didn't have high enough CP, or got questioned about what he was wearing. It's a good indicator that this is going to be a toxic group, so i rather wait for the next one.