ANDY'S ANSWER: Some people try drugs out of curiosity. They have heard that they are fun and want to know how it will make them feel. Other people use drugs because they think it will make them feel less lonely or depressed or help them forget their problems. Sometimes teens will use drugs just out of rebellion to their parents, and others because they've grown up with it and it seems normal to do drugs. The most common reason young people give for trying and using drugs is peer pressure. They want to fit in with their friends.
None of these are good reasons to do drugs in my opinion, but that's what people most commonly say for why they do.