Why are people like this?

Why do people always expect everything to go their way? I mean, not everything has to be about them.Not everything in this world is always for fun. Why won't people just realize that some things will always be like that? Like school for example, classmates always tell me, "SOOOOOOOOO boring." Well no one said school should be fun. We came there to learn so we can have a life, not to have fun. It may be fun at times but not everything, everytime. I know I may sound pessimistic,but it's reality. The world isn't exactly a playground. It's not a place where we can just toss flowers anywhere at anytime. Sometimes we have to be serious and think that other people have their own lives and therefore have their own opinions of things. Not everything has to go your way. Sometimes it has to go other people's ways for once. This world does not belong to anyone.