Stiles wasn't trying to give Gabe issues or make him think that he didn't like the kid. However, he didn't actually know him. So when he does finally sit down he can't help but give the younger McCall a warm smile. "Hi."

Sitting down was better than standing up any day," Why don't you sit down with me and tell me all about yourself." Things that his older self would already know, but he wasn't his older self.