Running has lots of gross side effects that people who don't run aren't usually told about, I think so that they'll try running someday. There are three that I think would have pretty high ick factors for the general public: chafing, black toenails, and flatulence.
The chafing has only happened to me in a minor way because I don't run that much compared to people who really, really run, who will actually draw blood from all the chafing that happens wherever one of their bits rubs against another bit while they are running. They use Vaseline and Body Glide and all sorts of bizarre personal lubricants to keep it in check. All I and my thunderthighs have needed for protection so far is the compression shorts under my running skirt but if I keep trying to run more and further I'm going to get some of the self-warming KY Jelly and see how it works. Because, you know, then we just happen to have a thing of self-warming KY Jelly in the house.
The black toenails are also something I think are more restrained to people who really, really run, and are actually the best argument I can think of for not pushing the envelope horribly hard.
The flatulence is pretty funny. I guess running jostles your tummy and intestines in such a way that digestion turns into more of a challenge, because I don't have a farty diet and I'm not usually a farty person, but the day after a run is usually quite a farty day. The thing is, farts are funny. Black toenails aren't funny, chafing isn't funny, but farting is fucking hilarious. Especially since I work at home and I'm not embarassing or digusting any colleagues.
In other news, watched Flash Gordon last night. I think maybe that's the best movie ever, mildly improved by imagining Dr. Zarkov bursting into "If I Was a Rich Man" every time he appears on screen.