Have you ever noticed the division of people just by their interests in music? Like the kids who like the heavy metal and screamo stuff are usually classified as "Emo". Or how people's actions and personalities are kind of match the kind of music they listen to? For instance... The teens who like Rave or Techno music usually have "pumped up" personalities. Music is so influencing that people dress in a way reflecting their favorite kind of music.
I've seen kids that are around 7 years old and they cuss and try to dress like they are "thugs". At first I just thought it was because of their home life, but it wasn't. They like rap music like Lil Wayne. The kind of music that does talk a lot about sex, money and partying.
When I made the connection, I though of how I dress and my personality... I listen to all kinds of music. Mostly Rock, Screamo, Alternative Rock, Pop-Rock, and some Pop. I have noticed that the mood I'm in usually determines what kind of music I'm in the mood for. Also how I dress determines the music for the day.
So just think about it.... Next time you see a guy sagging, a girl with puffy crazy hair, or a guy with all black on, they could be acting and dressing that way because music is very important to them and they reflect their favorite type.