A man walks into a bar and notices a sign that says "Free drinks for life if you can make our horse laugh." Intrigued, he asks the bartender about the sign.
The bartender explains that the horse belongs to the bar's owner and has never laughed before. The man decides to give it a try and walks over to the horse.
He whispers something in the horse's ear and, to his surprise, the horse starts cracking up laughing. The man goes back to the bartender and claims his free drinks for life.
A week later, the man walks back into the bar and sees a new sign that says "Free drinks for life if you can make our horse cry." Determined to keep getting free drinks, the man walks over to the horse and whispers something in its ear.
To his amazement, the horse starts crying uncontrollably. The man goes back to the bartender and once again claims his free drinks for life.
A month goes by and the man returns to the bar to find a third sign that says "Free drinks for life if you can make our horse stop laughing and crying." Confident in his abilities, the man walks over to the horse and whispers something in its ear.
The horse stops laughing and crying and simply stares blankly at the man. The man goes back to the bartender to claim his free drinks but the bartender looks at him and says, "Sorry, you didn't make the horse laugh or cry this time. You'll have to pay for your drinks."
The man is confused and asks the bartender, "What did I do wrong?"
The bartender chuckles and replies, "The first time you told the horse a joke, the second time you showed it a sad picture. But this time, you told the horse you'll be back next week to ask for credit, and that was enough to stop it in its tracks!"