Happened a few years ago. Patrick came on just after Rome and sadly, all I listen to is ESPN radio. Anyhow, some caller called in about some random topic (sports related) and strongly disagreed with Dan. The two got in a argument on air and it continued through the break. Eventually, Dan hung up on the guy and with 20 minutes left of the show, went on a tirade about the guy. Then he branched off into some philosophical rant about how soceity must be messed up if people agreed with the caller, blah blah blah, and then he basically said, "You know? Im dont, this is just enough for me today. Im not going to sit here and listen to that garbage from someone like that." He then chose to go off air with roughly 15 minutes left on his clock.
The next day, he show did not air.