hey, im a teenager just getting out of my teenager years and like you, ive been extremely happy.
i think one of my reasons for my happiness is feeling like im needed. and theres a definate reason for this.
when i was a junior in high school i noticed that there were a ton of people who ate lunch by themselves, were crying in the hallways, cutting themselves, etc... it seemed like they didnt have many friends who cared about them so whenever i saw them i would always go up to them and ask them how they were doing, if they needed someone to talk to, etc..
it takes a while for a person to be able to open up to you but once they do they trust you. you instantly become their best friend for the simple act of showing them that theres actually someone who cares. sure it doesnt seem like much to just say 'hi' to someone who looks lonely in the halls, but it has a huge effect on them. and its not like theyre bad people either. in fact, most of my best friends are the ones i made by doing this. heh, sorry this is so long, but its sorta complicated in a simplistic kind of way.
this didnt seem so meaningful while i was in high school.. but when i graduated i had about 3 people come up to me and tell me how much this meant to them. one even told me that if i hadnt talked to her she would have gone through with suicide.
so congradulations on being happy! now go spread that happiness around to your less happy peers! heh, just a thought