Q: What’s worse than finding a worm in your apple?
A: Finding half a worm!

Explanation: Imagine biting into an apple and finding a worm.  Yes, that is a very unpleasant thought because your apple is most likely not in very good condition.

Now, imagine biting into an apple and finding only half of a worm.  That means that the other half is in your mouth!  Yuck!!

This joke is funny because it sets up the expectation for something bigger, worse than a worm, and then surprises us with less than a worm, only half of a worm.

So, why are there so many types of apples?