One day, Harry and Sarah were having a petty argument. 

After shouting back and forth, Sarah finally says, "Let's make a deal. To end this argument, you admit that I am right and I will admit that I am wrong." 

Harry thought for a moment, agreed, and asked her to go first. 

Sarah replied, "I'm sorry Harry, I am wrong." 

In response, Harry shouts happily, "You're right!"