Here are some ways it's used:
* "You've got wool in your head if you think you can win that race!"
* "He's got wool in his head if he thinks he can get away with that."
* "I must have had wool in my head to forget my keys!"
The expression likely originates from the image of wool being tangled or blocking someone's thoughts, creating a sense of confusion.
It's important to note that while the expression is usually humorous, it can also be slightly insulting, implying someone is not being logical or reasonable.