I'm good at my job( which is retail). I have many customers I'm friendly with and on a first name basis. I show every customer nothing but respect as a human being. Some people are just fucking pieces of shit and are totally uncouth.

Here is a list of grievences; won't acknowledge me at all when paying, do not greet me, use the phrase "gimme", refuse to hand me their money and just throw it on the counter (often while I have my hand out), are on the phone while paying (my favorite is when they apologize to the person on the other end if the line), will not thank me.

I've seen children more well mannered than some of these so called adults. I treat everyone with respect, which is why I'm well liked, but some people are just assholes. As you said, refusing to reciprocate my respect is an easy way to lose it.

A wag of the finger to you.