Supposedly, if you stand in a crowd and look up for a while, you'll find a bunch of people will also do it. I've never tried it.

But I used to try that thing where they say if you stand in an elevator and face the back wall, people will also do it, but it never worked for me. Maybe I was too freaky, and they just figured I was strange. Would be interesting to see if a handsom man in a business suit, or a smartly dressed, pretty woman tried it if it would work. Hmmm....