The point is that most of the differences between people of different regions or fans of different schools are trivial and are more a product of exaggerated stereotypes than anything else. An outsider with no preconceived notions or emotional ties to any region or school would hardly notice any differences at all.
Hmm having said what I just said about people in general I disagree that there are no differences amongst fanbases. However I find that in general fanbases break down into two camps: doomsayers or triumphalists.
Minnesota Vikings fans are perhaps the most neurotic and doomsaying fanbase I've ever come across. Fanbases that are constantly waiting for the other shoe to drop and always expecting the worst from their team in big moments. Fans of teams like the Vikings, we can't help it but doomsay...it comes like breathing to us. Even upbeat comments about our team are couched in a sense of doom. My buddy at work told me I'm "negatively optimistic" about the Vikings which is a succinct way of putting it. Other fanbases that I've come across that are doomsayers are Georgia Tech fans, Notre Dame (post-Holtz era) fans, Chicago Cubs, Atlanta Falcons, Toronto Maple Leafs, etc.
Triumphalists fans are always believe their team is the best and always expect victory even if their team isn't the greatest. These are usually the fanbases everyone hates. I must say in my traveling around the country the fanbases that stand out most in this category are Alabama Crimson Tide fans (who are almost in a league of their own), Chicago Bears fans, Georgia Bulldog fans, Green Bay Packer fans, and LA Lakers fans. Some of those teams you would expect to have arrogant fans but the ones that irk me most are Georgia and Chicago Bears fans because to me they have very little historically to be triumphalist about yet it never stops them.
Historically I would say that Notre Dame fans are probably triumphalist however the past 20 years have been damaging to our psyches.