Green (gameverse) was pretty much told his whole life by his family that he was great and wasn’t told how to treat other people.
That’s why he’s so rude to Red and his grandpa. He actually really loves his grandpa, and considers Red his friend (friend and rival? Why not?).
Most people can’t put up with him. That’s why he puts so much energy into competing against Red.
Sounds viable to me. And Red is the only one who could put up with him, perhaps…
Thanks for the submission!