Lakia Amalga and Karakida Hanto in Kamen Rider Gavv (a paler shade of it, anyways, as they're teammates)

Emu Hojo and SHIN Dan Kuroto-Shin in Kamen Rider Ex-Aid (they just straight up hate eachother.)

Matt and Tai from Digimon (You cannot tell me Tai is friends with that fraud they are never NOT beefing and trying to outdo eachother)

YOU the viewer and your least favorite media that you like to talk about.