Changing hair color or style is a bit like buying a new frame for a favorite painting. It doesn't change the essence, just the presentation.

Of course, the trick to chosing a picture frame is that the frame needs to be pleasing of its own merit, yet sufficiently understated that the painting, not the frame, is the center of attention. Unfortunately, there are a lot of gaudily framed paintings in the world, and there are a lot of people with gaudily framed faces as well.