Whoever you're rebelling against -- The Man, your parents, corporate America -- if they change their habits, you have to change yours. What you wear, what kind of music you listen to, has to change every time their tastes and ideas change. Everyone has a PC? You have to get a Mac. Macs becoming the hot new thing? Time to go Linux. Every time something turns "mainstream," you have to change your lifestyle. You're on their schedule, not yours.
As the brilliant lyricists Green Day once said:
The minority, regardless off what the minority (or majority) stand for. So taken to its logical extreme, if your goal is just to be a rebel, instead of an actual belief of some kind, you'd actually have to switch sides once your side wins. For instance, once upon a time, you were in the minority if you considered all races to be equal. Nowadays, that's a majority point of view in America. If you want to be a rebel and buck the majority, you are going to have to start being a racist.