Greg is a cheerful and kind old man, as evident when he gives the player a fishing rod at the first meeting. Greg also admires hard worker, in fact he rewards the player a fishing pole when the player has more than 50 fishes in the pond. Being a fisherman, Greg loves fish a lot.
Ironically, Greg is appears to have no friends, despite his kind and cheerful personality. This is because he is never shown in random events and is never spoken about by others. Despite living with Zack, he is never mentioned by Zack at any point in the game.