In a moment of madness in 2000, while in Japan, I cut shoulder-length hair with a razor. All the kids at my high school loved it and for a few days they were going around asking to rub my head.
Japanese have a word called “shitsu-ren”. Shitsu means lost and ren means love. So the traditional story is that young men shave there hair when they fall out of love, or break-up with their girlfriends.