do it! experiment and have fun
Shave your head and tatoo a swastika on it.<br />
Now that's rebellious.
Get a mohawk instead ;)
Colour experimentation can look like someone's having an identity crisis if not done well :/ How about the emo... don't girls love that? ;)
I think colors like purple and blue, with some yellow. I would not do it because I don't like being looked at, but I find it very interesting when others do. Too much alteration concerns me, but temporary hair dye is simple and inexpensive.