My most (and at the same time least) favorite one went like this. I had completely redesigned a legacy system, included a whole bunch of warning dialog, and written documentation. The user has problems. I go on site, examine the problem. "Didn't you read the documentation or pay attention to the dialogs?" I asked. "We don't have time to do that," came the response. I replied.
George
Ubi caritas et amor, deus ibi est