Two faced bitches

You know what I absolutely hate? People who act like they are best friends with someone then actually totally act like they hate them behind their backs. The prime example that I see is with this girl in my school i will call "Ann." Ann acts like she is best friends with "Lily" when they are together, but then as soon as Lily leaves, Ann says things like "WOWW she is so effing annoying i hate her." I want to ask Ann why she keeps hanging out with Lily, even though she "hates" her, but Ann is just this immature, two faced bitch who has no right to have friends at all, if she treats them that way. ANN IS THE BIGGEST BITCH I KNOW.