Why do people yell for no reason
Because they watch "reality TV" and think that's how they're supposed to talk.
Most people have a reason
People yell for various reasons but the main reason is maybe because they are annoyed and angry.
If it really is for no reason then it could be a mental condition like bipolar disorder. My nephew is this way
When they are annoyed, angry, or upset they might just need something to help vent their feelings
They get frustrated easily or like the attention of everyone looking at them while they cause a scene.
they just want to...:P
It is sad but true that there are some people that like to be mean. Good question.
Because they want to intimidate and I'm not a big fan of yelling or screaming they are other ways to get your point across
Simple they have anger problems.