I like Mordecai's character, especially when he and Rigby are off on their wacky adventures (which is basically every episode) but seriously though. Episodes that revolves around his relationship tends to be my least favourite ones.

https://preview.redd.it/qozlfmrt1bh41.png?width=300&format=png&auto=webp&s=24b416b07014b801b4ee4bbdd7389f3229cf69cc

https://www.youtube.com/watch?v=OtGmp1fdwTw&t=62s