Toxic elitism.
I'm pretty sad to see that hasn't changed. Doing a nice fractal run, maybe not being optimal, and having people leave unreasonably because "dps isn't high enough" or such stuff. I'm talking not even people leaving while failing, but people leaving because you don't optimally succeed.
Tbh I do feel like there should be some kind of report for these things or a leaving penalty of some kind, making it at least a little harder on people who act like that.
And to all reading I can only suggest be friendly, be helpful, and not only you're gonna succeed in content but you're also gonna have much more fun.
<3