A man walks into a bar and asks for a shot of rum, the bartender replies, "it's on the house", the man says thanks and sits down. He goes up again for another shot, and the bartender replies again, "its on the house",
the man sits down again. He goes up a few minutes later and says "Give me a beer", the bartender says once again "its on the house" to which the man replies, "Why are you giving me all these free drinks?" The bartender replies "The boss upstairs is fucking my wife, so I'm fucking his business"