Growing up as a teenager, it is very common to see different cliques of people in high school. The way these cliques form is when people share similar interests and traits with each other. A common interest between us teens is TV and the different shows we watch. The shows we watch (whether we know it or not) shape our personalities, style and interests to help us define ourselves.
It's funny to think about, but soon after Gossip Girl came out, many of the girls in my school started wearing more expensive clothes, and the ones who couldn't afford them wore knockoffs. After South Park went on their campaigns about gingers not having souls, teenagers started to make jokes about having red hair and some kids took it so seriously that they made threats at South Park because of all the harassment they were getting.
After Jersey Shore came out, the latest concerns of teen boys became "My abs are way more ripped than yours" and "I've gotten with more girls than you." Girls, on the other hand, were trying to turn their skin orange through tanning booths or sitting in the sun for hours without sunscreen. It is a real reality that children growing up take what they see on TV seriously and try and act like the characters they see. This is not to say that everyone immediately does what they see on television, but it is definitely not ignored, either.
It's also not to say that everything on TV is bad for kids, because sometimes good things are taken from the shows teens watch, as well. Entourage (although some might not think is the best thing for their kids to watch) shows that friends have to stick by each others' sides not matter what, and that one of the most important things is having a group of friends that you love and trust. Mad Men, even thought it might show a time where men had more opportunities than women, shows a time in which men treated women like gentleman which believe or not does rub off on some kids. These certain behaviors that rub off on teens help make them who they are and ultimately decide who their friends are, which is how the different cliques form between us.