Guy, why is this? (Or girls)?

because right now, that's the fashion. In the 70's it was big wavy hair, in the 80s it was teased. and in the 90s some even crimped it.

Hmm, Good question. I dont think its that the guys prefer straight hair on a girl because its straight, i think striaght hair often looks better. They want girls to look HOT. so sleeek hair, even if it looks fake, is a good thing. Gorgeous natural curls mean nothing to them. They dont really acknolage them. (: I have noticed all females in my school adore and compliment my hair when curly, because i think they see it as gorgeous curls, you know?

and as for girls, i have curly hair, and i wish it was naturaly straight, everyone with straight hair pretty much wants curly hair.

everyone wants what they dont have.

As long as it's natural I don't have a problem with it! I hate it when people force their hate into something that it's not. If your hair is straight so be it and leave it. Same if it's curly, if it's naturally curly so be it and leave it!

My wife's hair is wavy not curly and it's long and beautiful and I love it! And she doesn't do anything fake to her hair and I love it even more.

My boyfriend is the total opposite. I've got naturally dead straight hair and he prefers it when I curl it.

because its usually softer because you don't need to hair spray the curls. and you can brush your fingers through it without ruining your hair.