If I had a time machine...

... I'd go back 40,000 years and find the VERY FIRST hominid sonofabitch who ever scraped a sharpened clamshell against his face, and I'd haul his neanderthal ass out in front of all his clansmen and kick it up and down the pleistocene tundra --- and I'd make it clear that I would do the same in turn to the next cro-magnon who tried the same thing, in the name of all us guys in the future who as a result are now stuck with having to shave every day.

Yeah, I really don't like shaving.