Why school should wear uniforms?

Do you know why we should wear uniforms at school? I have no idea either.
School doesn't have to wear uniforms.
In winter,we have to wear school uniforms,but school uniforms are freezing.It's not warm enough to us. If we wear mufti we could wear what we want to and we are not going to be freezing or hot!
Here is another thing, if your uniforms are in the washing machine...
That would be really big problem.What can you do?
Mufti would be great clothes! You could wear what you want and there will be nothing bad happens.Well, some people may say uniforms are better,but uniforms make people look same...
This is my opinion of people don't have to wear uniforms at school.