Observations

I'd say the thing that bothers me most would have to be those who believe they ascend the general population and are truly the paragon of human existance. While this may seem rash, it's troubling that I know too many people with this trait. I can't help but easily tire of the routine of constantly being put down because said individuals need a larger ego boost--it's a waste of my time, and I'm not going to accept it any longer.
What frustrates me about these types is that they also believe they possess an infalibility of knowledge, or, put more simply, they are never wrong. Debating, arguing, or pointing out the fact that they are wrong or why they can't be correct is futile, as said egomaniac does not want to hear it, and will argue forever until you decide, for the purpose of shutting them up, that the fact they are wrong no longer matters. When they do finally learn, through sheer fact or simple practicality that they are, indeed wrong, the person suddenly shifts to pretend as though they had no idea and were just guessing in the first place.
The really troubling thing, though, is that sometimes, these arrogant, pompous, and overly critical people even decide that their best friends are not worthy...that even the person they connect with most is not worthy of them...so much that they will, conciously or not, ridicule said friend or overlook them in lieu of others. Said individuals rarely see how much they mean to others until it is too late, and they finally force a severing of ties...all I can hope is that the cycle is not repeated again like it has been so often before.