Why do teenagers do anything to be accepted?

When you are a teenager you are so vulnerable, and you want to do anything to be accepted, but why is this? Teenagers do anything to be accepted not only because they want to fit in a specific group of friends, but also because of what people can think of them. When they feel that they are not fitting in their group of friends, they begin to do things, like drinking, consuming drugs, smoking, kissing a lot of girls, and with these kinds of things, they feel that they start being part of their group of friends. They also do this, because when you are a teenager you feel alone, and you want to be loved by someone. But teenagers don’t think about the consequences of doing these things. They could lead them to start an addiction, or something worst like dead. So, teenagers need to be supported and cared because they need to feel that kind of love.