P5 hair and high hairlines: there are two major reasons for this. (1) The "skullcaps" that many people use as the basis for their hair-growths often stop high up on the forehead. (2) Also, when you start hair lower down on the forehead, it's hard to get it to go back and over (or at least, it was pre-SR3; gotta do some new experimenting now). One can get around this by creating "bangs" or carefully arranging strands of hair in the front, but that takes a lot more work.