I've never gone with an unnatural color before. Except that one time I was going for reddish brown and my whole head turned maroon.
There's a lot of streaks all over my head. More than I origionally planned, even. But I like it so far. Sadly, there's a few spots in the back where my cousins (bless their hearts) didn't get the blue all the way to the roots, to there's bleached spots that show if I don't have my head just right. If if bothers me too much, I'll get it fixed, but I don't really mind at this point.