Have you ever had a customer you wanted to verbally abuse of commit acts of violence against?

Have you ever had a customer who really pushed you, that you wanted to retaliate against, but didn’t?

Disclaimer: I don’t think it’s right or productive to feel that way about customers (or anyone), and I don’t blame customers (or anyone) for the way they act/hold it against them, because I know they’re just doing the best they can with what they’ve got to work with (and what they’ve (or I’ve) got to work with is of course going to be less than is necessary to act perfect in all ways at all times, no matter what).
It also seems wrong to talk about customers behind their backs, because even though you could make the argument “well, they’re choosing to come into the store, they signed up for this”, they only expose themselves to us and to the chance that we’ll be jerks about them behind their backs because they have to, not because they want to. I also feel like we’re duty bound to be impassive and non-judgemental with them, because if we acted like real people with them they’d never feel comfortable asking us questions or anything.
For some reason, though, I’m still allowing myself to act in a way contrary to everything I just said I believed in by asking this question. I know, I suck.