* Customer calls in angry about a legitimate problem they're having, but their anger is 2-3 orders of magnitude larger than the actual severity of the problem.
* Customer attacks and berates the CSR, often to the point of tears, before demanding a supervisor.
* Supervisor takes over the call, apologizes profusely for the "incompetent" employee, showers the customer with account credits and so on, and maybe (but often not) fixes the actual problem
I'm not necessarily blaming the supervisor. If they pretended to have a backbone and the customer managed to escalate beyond them, then they'd be the one thrown under the bus while their manager verbally fellates the customer. It's very clear at basically all levels: the employee is 100% expendable, while any risk of the losing the customer's business is unacceptable.