Johnny says to Miguel, "We do not train to be merciful here. Mercy is for the weak. Here, on the street, in competition, a man confronts you, he is the enemy. An enemy deserves no mercy. Is there a problem, Mr. Diaz?" In Karate Kid, Kreese gives this same speech except at the end he says to Johnny, "Is there a problem, Mr. Lawrence?"
Miguel wears a blue LA Dodgers jersey while training with Johnny. In the original The Karate Kid (1984) film, Daniel Larusso wears a blue San Diego Chargers jersey under his costume at the Halloween dance, where he is ultimately confronted and defeated by Johnny and the Cobra Kai gang and then saved by Mr. Miyagi. Ironically, the Chargers relocated to LA in 2017, and Johnny is now in the role of Mr. Miyagi from the original film.
The style of martial arts taught at the Cobra Kai dojo is based on Tang Soo Do and Shotokan Karate (the parent style of the former). Tang Soo Do is the Korean transliteration of Okinawan Karate's former name To-te which means "Way of the Chinese Hand." Although the Cobra Kai uses Japanese terms like Dojo and Sensei throughout the whole series, the more accurate Korean equivalent terms would be Dojang/Kwan and Sabumnim or Sonsaengnim (head instructor; both are used in Tang Soo Do and Taekwondo). Sensei Terry Silver in the fourth season would give commands in Korean since Cobra Kai Karate is a Korean-based discipline.
When Johnny Lawrence fills out a commercial insurance application for Cobra Kai, he lists Reseda as a city which he lives in and where the Cobra Kai Dojo is located. In reality, Reseda is not a city but a neighborhood in the San Fernando Valley region of Los Angeles.
When Johnny Lawrence is at the Cobra Kai Dojo filling out a commercial insurance application, he lists 7428 Saticoy Street Apt 2, Reseda, CA as his home address. 7428 Saticoy Street is actually located in Van Nuys, CA but South Seas Apartments, the original location of Daniel LaRusso's apartment when he was a teenager, is located at 19223 Saticoy Street, Reseda, CA.