Why do books not make you laugh as hard as standup comedians do?

Have you ever read a book that had you on the floor laughing?

I asked a friend of mine for a recommendation of a funny book and he told me he thought James Joyce’s Ulysses was hilarious – I won’t be asking him for book recommendations again.

I’m talking about Chris Rock, Ricky Gervais, Billy Connolly type pain-in-your-sides laughter.

But in a book.

Why is that so hard?