In most cases, it is very beneficial for teenagers to fit in. At one point or another, every teen has wondered what someone else thought about them, whether it was negative or positive. It's pretty obvious, like on Facebook, there are many little games, where you like someone's status, and in result they claim to truthfully tell you what they think of you.

Teenage peer pressure usually is the influence someone else has on the way you dress, or how you act. No one desires to be that one person that sticks out like a sore thumb. But it'd be the better decision in some cases, otherwise it could end badly.

"Come on, just take one drink!"
Teens are pressured to drink alchol more than you may think. According to the National Household Survey on Drug Use and Health from the U.S. Department of Health and Human Services, 74.3% of high school students have tried alcohol.

"Stop being a party pooper and take a smoke!"
I doubt anyone says party pooper anymore, but someone has been in this situation. The American Lung Association has proved it. According to the ALA a whopping 3.1 million teenagers smoke.

Believe it or not, there is such a thing as positive peer pressure. Like teens being pressured into trying out for a sports team, joining the band, or even trying an advanced class. Which all equal to be better in the long run. Be yourself and no one else, do what makes you happy. Don't let anyone influence you in doing anything your not interested in. "Innovation distinguishes between a leader and a follower."
- Steve Jobs