Yuk! Also, never shake a man's hand while he is eating a sandwich.
Yesterday I was at the local mall eating a Subway sandwich when I see a husband and wife from my neighborhood pass. He is looking unusually scrappy. He is always somewhat scruffy, but now even more so. Long silver hair and scraggly white beard. He likes to brag that he retired at age 48. Anyway, he comes by and puts out his hand for a handshake. I olbilge and carry on the small talk. Now I don't want to touch my food. I have no idea where his scrappy hands have been.