Every cohort has at least a few of them. Students who will do nothing but complain. Complain about how being a grad students sucks. Complain about how being in academia sucks. Complain about how their adviser sucks. Complain about how life sucks. About how research sucks. The one thing that doesn't suck is their undergrad institution. Though I wouldn't be surprised if they used to complain about said institution while working towards their undergrad degree.
And I get it, I really do. Grad student life can be challenging at times and venting can be a good way to get rid of some of that frustration. I also totally sympathize with fellow students whose data aren't working out the way they had hoped, whose family conditions are far from optimal, or who simply don't get along with their adviser. But those are typically not the ever-complaining students. In my experience, the ever-complainers tend to have no more reason to complain than any other grad student. They almost seem to complain for the sake of complaining. It's what they do.
I'm not saying their complaints are not valid. They may very well be. But if all you can do is complain (and talk about how your everything is so much better at your previous school) without ever trying to improve your current circumstances
despite all the advice people give you, then yes, I might get annoyed. Perhaps grad school isn't for you. It's not as if it's your only option. Or perhaps you should change advisers or institutions
but that's advice and you won't take it. Or, dare I say it, perhaps you should change your attitude. Because if you decide to finish your PhD, things will inevitably get harder down the road, and feeling miserable
all! the! time! isn't going to help. Plus, a nice side effect may be that others won't resist talking to you so much
and stop hiding in their offices when they see you leave yours.
While my glass does tend to be half empty and while at times I do complain more than I probably should, I don't think I'm that person. Not quite yet at least. But I
should practice what I preach. And that's why I just deleted a very whiny draft I was about about to post. Because things are really not that bad. I do research I like, I have an adviser who cares, and I don't have a two-body problem. Some nice data would be good, but I'm working on that.
Now I just need to continue working on my attitude.