I hate bad, asshole customers.
But I hate nice customers more.
When someone is really mean to you, you're completely justified wanting to kill them or inflict egregious bodily harm on someone. When they're really, really NICE but EXTREMELY annoying, you have no viable excuse for wanting to murder somebody in their sleep over it.
Also: I hate the crazy lady who works in the fitting room because she never ever shuts the fuck up. She's a hundred and five years old, has worked at the same store since the glaciers receded, and hoards hangers in the back like a fucking squirrel with acorns. She talks and talks while you're trying to work and nobody has the heart to tell her to shut up. Even though it's really disruptive. Neither does anyone have the heart to tell her to stop coming up to the counters while people are working and digging straight under their thighs for more hangers to hoard. If she wasn't ancient and a woman, thsi would probably be sexual harassment.