You should like who you decide to like, not who your friends tell you to like. Like in this part of the song it says how this girls friends don't like the boy that she likes "He wanted her she'd never tell that secretly she wanted him as well but all of her friends stuck up their nose and they had a problem with his baggy clothes". Also in this part it says how she doesn't think this boy is good enough for her "He was a skater boy she said see ya later boy he wasn't good enough for her".
You never know, maybe someday that guy you turned down will end up being famous or something like in this part of the song "Five years from now she sits at home feeding the baby, she's all alone she turns on tv guess who she sees skater boy rockin' up MTV".
If you just meet somebody you can't judge him or her right then and there you have to get to know them like in this part it says how she didn't get to know him "Too bad that she couldn't see the man that boy could be there is more that meets the eye I see the sole that is inside".
The moral to the song is don't judge a person by what they do or don't have. You should always get to know someone before judging them in any way. You know the tables just might turn and the teasing you put that person through might come back to haunt you. So the next time you see someone who might look like they don't have what you have, or there not good enough for you just remember, you can never judge a book by it's cover.