The behaviour I have the most difficulty understanding (as a person who is admittedly not the best at understanding human behaviour) are people who are really cliquey. You know, the ones who shut off %99.5 of the human race except the ones who are just like them. You think this type of tribal behaviour would end in high school but it really doesn't, it just gets more sophisticated and less obvious. The kind of people that are only nice to others that align perfectly with them and they're kind of cold (or an asshole) to everyone else. 

I think I have such a hard time with people like this because I'm the exact opposite. If someone's heart is in the right place and they don't annoy me or go out of their way to piss me off, then great, we're friends. I don't really care whether or not we fit together perfectly or compliment each other in just the right ways. I don't even care if we're on the same page in terms of our beliefs or politics, just so long as someone is reasonable I can overlook all of that. 

The kind of people I'm talking about, however, basically write off everyone they don't see themselves in. It's like they're sheltering themselves from the majority of the human race because it's easier that way. I'm so sick of this type of person that when I identify one, I begin to keep a certain distance from them right away because I know that trying to get close to them is an exercise in frustration as they've most likely already written me off within ten seconds of meeting me. Sometimes this type of person is benign but sometimes, they're catty and tribal to the point where it feels like walking on eggshells in their presence. 

The absolute worst is when people with this tribal mentality form a tight knit clique, develop some kind of superiority complex and start to judge everyone through that lens. 

I actually have a complex now when it comes to these people. A lot of the time we can just go our own separate ways peacefully even if we have to work or study together, but if I sense that they don't like me for arbitrary reasons or worse: they're gossiping about me or others I care about, then things are going to get ugly 'cause I hate that shit. Fortunately I'm very adept at spotting it now.