Most teenagers go through periods when they are unsure of who they truly are. When they reach adulthood it is more likely that these young adults have a better sense of their real personality then someone who didn't go through this struggle. This is mostly do to the fact that if you have this problem at some point you tend to study who you really are and in the end know yourself better. A child who is popular is much less likely to go through this issue.
As children get older and begin high school there is an increased importance of friends. As teenagers begin trusting and telling secrets to their friends, their relationship gains a sense of loyalty and obligation. When a teenagers finds him or herself thinking like a someone else it develops into a friendship.
If a strong bond occurs with someone normally of the opposite sex dating might occur. Dating is a very loose word which can mean many different things. It can mean going out in a group to have fun, going out in a group to get to know each other, or just two people going out to see a movie. After feelings have grown between two people they sometimes experiment sexually with each other.
Most teenagers' first practice with sex does not involve another person. Many young adults have sexually related fantasies about someone they know (or someone they don't know for that matter). It is also fairly common for adolescents to masturbate.