The Karate Kid/Fridge

Original films:

• Why does Daniel choose the Crane Stance and kick in the final round? As has already been noted, the move is obvious and nigh-impossible to execute. Simple: Due to the "Sweep the leg" thing, Daniel's left foot can no longer support his weight, but rather than throw in the towel, he gambles everything on a desperation move, the one move he actually has a chance of performing. And it works.
• A bit of fridge horror here, but much of Johnny's attitude mimic's Kreese in every way, Johnny is considered his best student and a champion before Daniel broke his winning streak. Seeing how Kreese was treating the other students for failing to follow his teachers such as forcing one to do push ups on their knuckles and Johnny himself being strangled half to death for his failure to win against a crippled Daniel; it seems to be implied that Johnny may have had to endure a lot of abuse from Kreese in order to make his way into the top ranks of Cobra Kai. Hence why he's arrogant and temperamental to those that confront him. Him rolling a joint back then could have been the PG version of him turning to drugs, but it also could imply he uses it to cope with the pain and abuse he's endured over the training.