What you are describing with the emo kids you know is called Dependent Personality Disorder. Its something that was largely ignored for a while and is showing in today's younger generations. It can be quite serious and only gets worse when people ridicule them. Its no laughing matter. Self-injury is also nothing to take lightly. My girlfriend is a self-injurer. Its a coping mechanism. There are some emo kids who do it just as a trend though, and I hate it because once you get something as a trend, the real problem is passed off as just looking for attention.