I have been to a Jets game at Giant Stadium, Several games here in Washington, a game in Baltimore and in Philly. Other then a few fans at the Jets game telling me that it would be best for me not to wear my Bills jacket in and keep any celebrations to a low key, I never had a problem. Most everyone was very civil and would talk about each others team pretty nicely. The key is don't be an ass, don;t get drunk and hold your tongue on celebrations, and don't whine if the other team gets ahead or scores.