Why are a lot of girls snobs? Are there a lot of snobs in the workplace?

Seriously in my school girls are so catty, its like if you dont have that super straight hair, cute clothes, and not girly enough they wont talk to you and make fun of you. so many girls give me dirty looks for no reason at all, like l have all girls gym class and wow l thought some girls were nice and then a week later they were all giving me dirty looks and gossiping about me and l barely knew and never said a word to them, okay sorry l couldn't be perfect looking, or girly enough. even when l try to be nice they give me a "whatever" look. lm not saying every girl is snobby dont get me wrong most of my friends are girls since they were only cool ones l meet. Most of my friends are tomboys and would be labeled as "goth" or "rocker/emo" but other than that l get lots of stare downs and get treated like an outcast usually from girls wearing uggs, hollister, abercrombie, that stuff, l dont why some girls cant just get along and not think everything is competition. its hard to find a decent cool girl in my area who is not so snobby =( and l know a lot of women dont mature either, even though lm a teen l encountered women who look their nose down on me why cant they all just stop? does anyone else feel the same? is this common in the workplace too : /