What's the difference between a cat and a comma? One has claws at the end of its paws and the the other is a pause at the end of a clause.
John really liked Sally. One day he got the nerve to ask her to the dance. She said yes. John was so happy. He wanted to make the dance perfect for Sally. He got a tux taylored, did his hair, and even took a shower. When the dance came around John was excited. Sally asked John for punch so he went to get some and there was no punch line.