Clash of the Titans

When is it exactly that girls learn the meaning of 'clash' in the clothes sense. I definitely remember coming to school one day and finding that unbeknownst to me, red and pink had become a socially damaging colour combination. It was in grade four. No one told me, so who told them? And why is it that all the truly interesting colour combinations were taboo? Suddenly only blue was a safe colour, and to be extra sure that you would be acceptable company, blue combined with blue. For the adventurous, blue with green or red. But blue was a must.
This attitude toward stimulating colours lasts a long long time. Especially in high school. In fact, most people never recover and wear blue until death or blindness.