I forgot to mention, I don't like stories where a main character is jealous (for whatever reason) of another character.
Maggie getting angry at Supergirl always saving the day and making her job seem worthless is a good angle, but I'm just not fond of that type of storytelling. I would have forgiven it and left it with the episode it belonged in, but the next episode saw James acting jealous over Supergirl and asking himself why he wasn't getting the praise for fighting crime.
Thankfully both stories were contained and I can tick the box, knowing we won't be going there again.