Howie Mandel may have something with his “fist bump” mentality. Touching other people can be freaky, especially if you don’t know where they (or their hands) have been.
Web Watch knows quite a few people who still refuse to wash their hands after using the restroom, sad but true. And we certainly hate being introduced to someone immediately after they obviously return from the restroom, as that initial slightly damp didn’t-quite-finish-drying-my-hands handshake is always a bit icky. We cringe now even thinking about it.