I can think of only one quite bad thing that was shouted at me in 6 years of working on the phone.
I'd taken an escalated call and the woman was getting more and more frustrated as the call went on as she was questioning the T's & C's and I was countering her to the stage that she knew she didn't have a leg to stand on.
Anyway, I finished with my standard, "Is there anything else I can do for you today?" and she said quite calmly, "Yes, you can come down here and suck my husband's cock!" and then slammed the phone down.