AITA for slapping my SIL’s butt during a family football game?
My family was having one of our usual backyard football games last weekend. Everyone was joking around, drinking, and getting competitive. My SIL made an absolutely incredible play and intercepted the ball. I ran over, grabbed her shoulder, and gave her a pretty firm slap on the butt while saying, “That’s what I’m talking about!” She immediately turned around and looked at me like I had two heads. I laughed at first because I thought she was just surprised, but then she said, “Don’t ever touch me like that again.” The weird part is that I honestly thought it was harmless. We’ve known each other for years, and I’ve always considered her family. But apparently I made her uncomfortable. Later that night, my wife confronted me about it. She said the way I described it made it sound like I had been waiting for an excuse to touch her. That really bothered me because I wasn't waiting for anything. Although, if I'm being completely honest, I have noticed that my SIL has been looking really good lately. I don't think I've ever said or done anything inappropriate about it, though. Now my wife is furious, my SIL won't really talk to me, and my family is divided. Some say it was just a football celebration. Others say there was something creepy about the fact that I specifically chose to slap her butt instead of just giving her a high-five. I genuinely don't know if I'm being made into a monster over one stupid moment or if I crossed a serious boundary. AITA?