I have had half head highlights done for years and years and I kid you not, my hair now behaves like two different hairs. Obviously the top half is lighter to look at, but it's got to a point where the behaviour of each half is so different, that I often wake up in the morning to poker straight dry coloured hair (top layer) and a darker completely curly and greasier bottom layer. I'm going to have to start getting full head highlights, ain't I?