In HM64, short for Harvest Moon 64, Gray isn't very social. In fact, he's extremely antisocial, and unless you get to know him, he doesn't talk much. He seems rude at first, but become his friend, and he'll like you. Even if you do, he won't talk much still, but he'll talk more.. Sometimes he doesn't even make sense. Oo' He picks on Ann because she leaves candy in the cabinet and forgets about them. You'll see a cutscene soon enough of him scolding her about stale candy.
Gray lives on Green Ranch. Green is his last name, as well as his sister Ann and his father Hall. Gray Green.. sounds catchy, eh? He helps out with the animals, and loves horses. But after a horrible accident years ago, he is unable to ride horses anymore. Sad, isn't it? Before that accident, he was more social, and happy. But now he's rude and a social disaster. ><