These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: The Karate Kid
YMMVs for the original film series:
Awesome Music: "You're the best, around, nothing's ever gonna keep you down!"
Bill Conti's score deserves mention also. Including the main theme derived from Survivor's "Moment of Truth." Survivor had the freakin' market cornered on rousing 80's anthems.
Memetic Mutation: Many things, most famously the Crane Kick in the sunset image. But some of the dialogue has achieved that point as well.
"Get him a body-bag! Ye-heah!" "Sweep the leg." "Johnny, you're a cream puff!" "Banzai!" "Daniel-san." And of course, "Wax On, Wax Off."
Moral Event Horizon: Chozen crosses this by refusing to help Daniel save a child's life during a storm. Just in case nobody got it, in the finale he holds a knife to Kimiko's throat and punches her lights out.
John Kreese came off pretty unsympathetic when he proceeded to choke his own student to death over losing a karate tournament.
Narm Charm: Glory of Love would've been a super ultra narmy and cheesy love song that Tastes Like Diabetes... if it wasn't performed by a pro like Peter Cetera, who makes it really charming.
Critical Research Failure Dre plays a mean DDR. Mei Ying then proceeds to beat him, by standing away from the screen, facing Dre, and focussing on upper body dancing. Completely disregarding the fact the way D D R works is that you follow the instructions on the screen. So unless she knows the song backwards and blind there is no way she could've gotten a high score.
That said, Reality Is Unrealistic. There are plenty of videos of people playing DDR blindfolded that are a quick search away, and playing in a turned-around position wouldn't be that far-fetched if she was really that familiar with the song. Given, that probably happened to be the one song she had totally down in that way on the game, but it's far from impossible if someone really good at the game cared to put the work in.
Awesome Music: About midway through the film, a Mandarin version of "Dirty Harry" by Gorillaz can be heard. Commence scooping up the pieces of your mind now.