The bartender asks the guy sitting at the bar: "What'll you have?"
The guy replies: "A scotch please."
The bartender hands him his drink and says: " That'll be $7," to which the guy replies: "What are you talking about? I don't owe you anything."
A lawyer, sitting nearby says: "He's got you there. In the original offer, which constitutes a binding contract upon acceptance, there was no stipulation of remuneration."
The bartender, not impressed, says to the guy: "Okay, you beat me for a drink. But don't you ever let me catch you in here again."

The next day, the same guy walks in to the bar. The bartender says: "What the heck are you doing in here? I can't believe you've got the audacity to come back!"
The guy says: "What are you talking about? I've never been in this place in my life!"
The bartender replies: "Crikey! This is uncanny. You must have a double."
To which the guy replies: "Thank-you. Make it a scotch."