Whenever I'm in a public restroom (by the way, Barnes & Noble keep some of the cleanest restrooms I've ever seen), I have to hold myself back from yelling at people who leave the bathroom without washing their hands. It's disgusting, and I usually end up leaving the store after that, because I realize that they could've touched anything in the store.
My supervisors at work used to keep Purell hand sanitzer at their supervising podium. I ended up going through entire bottles almost by myself. They stopped buying it. Now I'll have to start buying it, and keeping it at my work station.
And I can't stand washing my hands in the bathroom at my job (an electronics store). The place is always so filthy. I actually feel dirtier after washing my hands in that place.