Cat Napping has a very simple set-up: Tom and Jerry fight over the use of a hammock in the garden. The result is predictable T&J knockabout fun, with Tom unsurprisingly getting the worst of it. The animation here is up to the usual excellent Hanna-Barbera standard, and the gags are extremely funny, with Tom swallowing a bullfrog that causes him to bounce all over the place, being attacked by a lawnmower, and getting catapaulted so high into the air that he flies past an airplane.
My favourite gag comes right at the end of the cartoon and features that other T&J regular, Spike the bulldog: believing that he has Jerry wrapped up in the hammock, Tom proceeds to give it some hefty whacks with a baseball bat. The cat then reaches into the hammock and pulls out Spike's collar. Tom pictures Jerry in his mind wearing the collar and realises his mistake. His expression when he understands the reality of the situation is priceless.
N.B. This cartoon also features the first appearance of occasional characters The Marching Ants, who add to the fun.