There are ways of avoiding becoming tabloid fodder and therefore giving people license to pry into your private life. And there's a distinction between being an actor and being a celebrity. You may become a celebrity through acting, but you don't need to do so.
Why do you think so many actors are only half-developed people? It's very easy when you're a young actor to have these intense, explosive friendships for short periods of time, because you can control what's shown of you. Then you go on to your next job and reinvent yourself again. I think it's important to find something constant.