Fairy Friends and Neighbors/Just the Two of Us - S4-E11
Continuity mistake: When we first see Trixie and Timmy inside Timmy's large sand castle (or whatever it was), they were sitting at the ends of a long table. But when Francis destroys the castle, Trixie and Timmy are way closer together.
Answer: It's a joke. One cannot list all forms of entertainment. The list would never end. The boys were trying to convey how superior they were to the others, by saying that they were too good for comedy.