What is a "friend zone" and why does it exist?

[Supwithbates]

First post in OOT, pls be gentle.

I always hear about the dangers of slipping into the "friend zone" when you first meet a girl and start to spend time with her. What's up with that? I mean, I don't care if I've been friends with a girl for 10 years, if I think she's hot and obviously we can stand being around each other, why are they creating this artificial obstacle?

I do understand the feeling like "well we always hang out together, you're friends with my friends, I'm friends with your friends, how the heck would this work out if we had a messy breakup", but to that I say:

GAMBOOOOOOOOOOOL