I once called a particularly noxious user a 'brain-damaged redneck'. he was very upset, and sent in a formal complaint to the head of systems... me. i'd been on hell desk because three of the guys were out sick (gee, I wonder whatever could have caused that...) and the brain-damaged redneck failed to take note of my name. The formal complaint had very little to do with what had actually happened; I only recognized the incident because _I_ had made a note of the brain-damaged redneck's name, and, besides, I had a recording. ("All calls may be recorded for training and monitoring purposes.') We made sure to record _all_ hell desk calls after one too many "who are you going to believe, me or some lowly IT monkey" incidents.
When no action was taken, the brain-damaged redneck went to the extent of calling a formal meeting on the subject. i played the recording of our little talk, and put up his email complaining, and let the meeting compare them. The brain-damaged redneck no longer works at the company. Word got around that there was a new sheriff in town, and hell desk abuse incidents dropped markedly.