We used to eat out at least once a week with an assoaciate of ours & his late wife (sorry). Although they were very well off & could be quite snobby, she never washed her hands after going to the loo! It used to really irritate me, 'specially after me hinting that the soap smelled nice & the water was too or or cold! I'd have thought the racket of he dryer would have prompted her too, but no....
She'd stand there preening herself in the mirror, before walking back to the table to finish off her meal. She would often poke her fork in my dinner & say "Oh, that's looks nice, could I try it?". Aaarrrggg,
I've always keep a pack of wipes in my bag - just in case!