In my opinion, I think it all has to do with someones self-esteem and negative experiences in their life.

If you think about it, seeing things through, for example, a high self-esteem in someone, they're generally confident and overall happy with themselves and others. Someone with a low self-esteem are most likely the self-loathing type or overall jealous type when it comes to others.

Whether or not someones a bully or clearly disrespectful and rude, all people in comparison to this trait are one way or another in this state for reasons of either a harsh past experience, bullying by parents/family/friends, denial, attention, jealousy, or simply trying to cover up negativity or acting in a way to shut people out. Someone with low self-esteem will do anything just to bring someone else's self-esteem down below their bar. It's kind of sad to see how awful a low self-esteemed person's jealously, anger, and extreme dramatic behavior has become and all because someone seems better than them when they aren't. They want to bring people down low, so you'll feel what they feel and to show off that they are superior instead. Victims of low self-esteem need to feel secure and when they notice someones esteem is above their level, they attack. Soon the innocent victim becomes the pray and the pray no longer has to feel like the victim.

It's almost like a cycle of who's bigger, who's smaller. Who's superior and who's inferior. Almost to say,

'I'm bigger and better, I need to be mean and rude so people with fear me, that way no one can hurt me or try and bring me down.'