depends on the situation. Harass them when they are grocery shopping, no. But if you see them in public and say, "go Bills," or "hey, great game," that's totally fair and really, they prob appreciate that. If your in line next to them somewhere, having a conversation about a game or asking for an autograph/picture also does not seem out of line. Like most other things, it's context dependent. I live in Pittsburgh, and Poz's brother lived in the house next to mine. Poz lived there in the offseason and visited him during the buy week. I didn't harass him ever, but I'd say go Bills or something. He seemed to appreciate it, he was also perplexed upon meeting a Bills fan in Pittsburgh.