According to 247Sports the Green bay Packers have one of the most obnoxious fan bases in the NFL.

Matt Meltzer of "Thrillist" writes that the "Packer Backers" came in at 9th, and here is the reasoning:

"Ah, Green Bay. The model franchise. Not owned by some money-grubbing autocrat but by THE PEOPLE, and you’ll gladly remind anybody and everybody of that as you break out your certificate that proves you, too, own a piece of the team! Never mind that those certificates are about as valuable as that “share of a gold mine” you got on a family trip to South Dakota. Packers fans like to present a welcoming aura of friendliness (tailgating at Lambeau pre-game is actually a fantastic time), but make no mistake, they will turn (on you or anything around you) in a HEARTBEAT if things go south for the Pack. Just look what happened to Brett Favre when he dared play for the Vikings. Which Green Bay now collectively pretends never happened." - Matt Meltzer

Ouch.