I live in Maine now, and I am constantly surrounded by Pats fans. While the majority of them are just normal, decent, sports-loving folks, there is a very prominent subset of the most spoiled, arrogant, and obnoxious fans I have ever been around. I don't even go to my local bar to watch the Bills on Sundays anymore because I get trash-talked by aggressively drunk Pats fans. They expect their team to dominate, and when they don't, they pout. Every sports market has these types, but here it's an abnormally high proportion. They really drag the benevolent portion of the fan base down.
What's funny is that Mainers are always bagging on "Mass - holes", Boston, and all things related to the Commonwealth, yet they worship the Mass sports teams.