It’s always a bad idea to try to figure out why someone is rude, negative, irrational, abrasive, arrogant, or just generally neurotic. You’re much better off to simply make a mental note of what you observe and chalk it up as a phenomenon that is beyond human understanding. Then, most important, quickly move on to more productive matters.
Passive fascination with an annoying person is a harmless thought process. But if you allow your fascination to become active — i.e., if you feel a compulsion to find out why, say, a jerk acts like a jerk — you’re sending a message to your subconscious mind that your time is not very valuable.
Dealing with neurotic people is a job for professionals in the psychiatric field who get paid to be actively fascinated. But the rest of us should be humble enough to admit that we have no idea why neurotic people act the way they do — and let it go at that.