I think Karate Kid started the entire comedy action flick movie genre. The scene where Mr Myagi is drunk and singing and taking a sledgehammer to that car is a hilarious and classic scene. Wax on wax off? Forget about it.
Pat Morita's Mr. Miyagi was lovable, believable, and hilarious. Karate Kid actually has a lot of comedy to it despite it's story of Daniel-Son moving into a new town and having a run in with the local Blond, stuck up yuppie karate guy gang leader from the Cobra-Kai school. Daniel-Son makes the mistake of flirting with the bad ass, karate stud, gang leaders girlfriend, and gets himself nearly beaten to death before being saved by his new apartments maintenance man. This meeting begins a friendship and a mission to train Daniel-Son to win the Karate tournament against the preppy white boy gang from Cobra-Kai and regain his honor.
Mr. Miyagi trains Daniel-Son by having him make his mess of a house into a pretty bad ass, well landscaped, and fixed up house all for free. Daniel-Son paints his fence, his whole house, builds him a deck complete with a koi pond, landscapes his whole backyard, waxes, and details at least 7 classic cars all while Mr. Miyagi lounges, or goes fishing, or just torments him but never helps, or pays him. Daniel-Son goes along for awhile before he finally gets fed up and questions Mr. Miyagi's slavery like training technique.
Daniel-Son felt Mr. Miyagi was using him and not training him at all. He'll, he'd raised the old man's property value by 200%, and they hadn't thrown a single kick, much less put on a GI. All the while the big tournament was getting closer. Fed up with being hustled for free labor Daniel-Son finally stands up to Miyagi who then proves to Daniel-Son you can be a slave as well as train to be a bad ass karate master at the same time with a creative enough slave master.
Daniel-Son had learned karate by painting the fence, building decks, and waxing cars becoming a great fighter without even knowing it. And, in the process, Karate Kid perfected the buddy comedy movie.