Why People Are Bullied

I was recently asked to write a post about the reasons a character would be bullied.
Why are people bullied?

In grade school, I was teased, jabbed at, and generally unliked. Why? Frankly, I think I deserved it. I was a stuck-up little snitch, teacher's pet. I thought I was smarter. (Give me a break, I was in fourth grade.)
I become quite good at comebacks and snide comments. I was both the bullied and the bully. Needless to say, those were lonely years.

So, speaking from experience, bullies will find any excuse to tease. And sometimes we give them that excuse.

The Bully
It is said that people bully from low self-esteem. Yes, that can be true. But for people who have a specific target it's either because they hate that person for some reason (i.e. target's father fired bully's father) or the target gets is amusing to tease.
Occasionally though, bullies think it's cool. Everyone else is picking on a certain kid so they do it to be with the crowd.

The Bullied
Here's a little gem of wisdom for those being teased; if you make a big deal out of it, they will too.
Sometimes, people are picked on because they're obnoxious, stuck-up (like I was), or they're simply easy prey. If a person slouches as they walk down hallways, doesn't speak, avoids people, and thinks ill of themselves, that's just begging for trouble. You might as well paint a hang a sign on your back saying, "Tease Me!"
Have you ever wondered why the popular are popular? It's not because they have designer clothes and the perfect hair, though people would like to believe that. It's because they have an air of confidence that draws people to them like a magnet. Confidence is the most attractive trait.
So it stands to reason that if you have a bullied character, they will lack confidence.