If you think bullying is normal, you're less likely to say or do anything about it. Getting teased, picked on, pushed around, threatened, harassed, insulted, hurt, or abused is not normal. Bullies will go away if you ignore them. Some bullies may go away. But others will get angry and keep bullying until they get a reaction.
All bullies have low self-esteem.
That's why they pick on other people. Some bullies have high self-esteem. They feel good about themselves, and picking on other people makes them feel even better. Most of the time, bullying isn't about high or low self-esteem. It's about having power over other people.