I know your secret

Two boys were talking and the one said to the other, “There is a easy way to get what you want.” 

The other boy said, “How?” the boy replied, “Tell people you know their secret.” 

The boy jumps up and runs to his dad, “I know your secret!” The dad replies, “Please don’t tell your mom heres $10.” 

The boy then runs to his mom, “I know your secret!” The mom said, “Please don’t tell your dad here’s $15.” 

The boy then decides to try it on the mail man, “I know your secret!” The mail man opened his arms and said, “Come, give your dad a hug!”