A hot mic can be very unfortunate for the person who does not realize they are saying something out loud for thousands, if not millions of people to hear.
During a college football game between the North Dakota Fighting Hawks and Southern Illinois Salukis — an upset referee was highly pissed off with his equipment, so he let his frustrations out to other officials near him.
Only problem there is that everybody in the stadium heard what he said as well:
As for the game, the Fighting Hawks went on to win, 44-21.