I don't want to start an argument (although in the offseason before camp starts there really isn't anything better to do)... but I take offense to your statement. I have lived in Pittsburgh for 5 years now, and that city is filled with almost nothing but trash. I went to watch a preseason Bills/Steelers game a few years back in a bar (with friends who were Steelers fans). I am a very shy person (and it was preseason) so I wasn't cheering, just eating my food and watching tv. People were screaming at us, cursing, and generally being asshats over a preseason game. I have stopped going to Penguins games, after a high-fived a 4-year-old girl in a Sabres jersey after Buffalo Scored and was loudly called a "!@#$ing !@#$". While I don't have a huge sample size to compare, I have been to a Sabres game in Colorado and in Washington. In both of those cities, local fans would stop and say "where are you from", "here is a fun place to eat" "hope its a good game", etc. In Pittsburgh, I would probably have a heart attack if anyone demonstrated that civility.
This should explain how bad it is: Last year I defended a woman wearing a Tom Brady jersey in front of me at the grocery store, who was being harassed by idiot Stiller fans.
In summation, yinzers are basically the scum of the earth.
ETA: http://www.sbnation.com/2009/1/29/1642841/tsb-in-tampa-the-prototypical [That should make everything clear - that is the year-round acceptable Pittsburgh dress code]