I'm constantly grateful that the company I work for (a major bank) doesn't make us put up with that. There's a certain level of shit we're expected to deal with from callers, but if they start getting outright abusive we can end the call, and if it's a trend with the customer, or if it's especially bad, the customer's accounts are revoked and we mail them a check.

One dude screamed that I was a N-word (especially confusing because I even sound whiter than mayonnaise), I escalated the call to our management team, forwarded the call log to my manager, and the customer's accounts were closed within a week.

I mean it's still customer service, and it still sucks, but at least the worst shit we don't have to put up with.