Why is popularity a big thing in school?

I don’t understand…I’m not popular…I only have 2 real friends in my life that aren’t my family members…The rest are just there…or acquaintances if you will… I’m not a popular kid is the main point…But what is it? I was in elementary school…middle school I’m barely known, people make fun of me behind my back. But what does it matter? I know who I am, they only make fun of me since they know that I’m higher than what they are to themselves. But…Why is it such a BIG role or….big thing in schools…Were you popular? Why weren’t you popular if you weren’t? And most of all…Why does it matter? Please, I’m eager to know this answer to this very…very unreal reality that we call popularity.