The bartender asks the guy sitting at the bar, "What'll you have?"

The guy answers, "A scotch, please."

The bartender hands him the drink, and says, "That'll be five dollars,"

"What are you talking about? I don't owe you anything for this."

A lawyer, sitting nearby and overhearing the conversation, then says to
the bartender, "You know, he's got you there. In the original offer, which
constitutes a binding contract upon acceptance, there was no stipulation of
remuneration."

The bartender was not impressed, but says to the guy, "Okay, you beat me
for a drink. But don't ever let me catch you in here again."

The next day, same guy walks into 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, "I'm very sorry, but this is uncanny. You must
have a double."
"Thank you. Make it a scotch."