I can't remember actually meeting any Steeler fans in person and not getting along with them. They're superfans, and so much of their region's identity is wrapped up in that team that sure, the collective "Steeler fans" can be annoying. But that's true of literally every franchise that has an active fanbase.
Steeler fans individually generally know their stuff, love football, and are pretty willing to be good natured in person. It's one of the most down-to-earth, friendly cities in America, IMHO.
edit: Now, if you want to talk about Ravens fans...
I've lived in western PA for a long time and I've seen the ebb and flow of Steeler fandom. In the 90's they couldn't get over the hump, they lost a few AFC championship games at home and one Super Bowl to the Cowboys. The Cowboys won three titles in the 90's and more titles overall and the 49ers also had more overall Super Bowls at the end of the decade. They started to get chippy in the early 2000's with the losses to the Pats in 01 and 04. It went from we'll never get back to the top to "screw New England" and "They'll never be on our level!". Bitterness really started to set in and the focus on New England started to become a big thing
Then they won in 05 and 08 which put them back on top of the Super Bowl hierarchy. The Sixburgh stuff became insufferable, and it has been the "Stairway to Seven" ever since. I believe the Pats infatuation has several elements.
1.
Head to head in the playoffs: The Pats have beat them on the biggest stage 01,04,16. Two of those Steeler teams were heavily favored and lost at home.
2.
Image: They don't view New England as football area, how dare those snobby New England intellectuals/liberals challenge them for football superiority. Pittsburgh is very much still an Iron City drinking, kielbasa and pierogi eating, blue collar area, and they view Boston as a bastion of snobby elitists. The Steelers are always supposed to be the smash mouth team that represents that blue collar toughness. The Pats have been more offense oriented for most of this run and they view them has tricky and underhanded, not willing to hit you in the mouth. Which was not true at all of the early BB Pats teams. The fact that the quiet and intellectual team continues to outsmart them and win is infuriating.
3.
Legacy. They've had a great QB for the past 14 seasons and he has been denied a few rings by the Patriots. Ben has never beaten Brady and the Pats when it really counted. In fact Ben has only beaten the Pats three times, and one of those was in 2008 when Brady was out. All of the chatter on talk radio here leading up to the playoffs was how a win over the Pats would really cement Ben's legacy for all time. Throw in the fact that they view Brady as a pretty boy whiner and it makes for a lot of bad feelings.
4.
Spygate: They are convinced that they would've won in 01 and 04 had the Pats not been taping signals. They will bring this up constantly if the Pats come up in conversation. Hines Ward and a few former players have been beating that drum for years. It doesn't matter that Cowher has said many times that it didn't matter and not why they lost. The paranoia about the Pats persists to this day, look at Tomlin with the headsets on opening night two years ago.
5.
Asterisks: When they won in 2005 and 2008 they didn't have to go through the Pats to do it. That doesn't make those Super Bowls any less legit, however it is fun to bring up in conversation. It gets them worked up every time. It is almost as if the Red Sox had not gone through the Yankees in 04 and won it all. We'd all still be thrilled and it would still be an all time achievement for the franchise, but you know Yankee fans would still be saying how the Red Sox could never beat them when it really mattered.
The fear is real about the Pats reaching six titles. I think if San Francisco or Dallas were to win another Super Bowl and tie them they would be bummed but it wouldn't be that big of a deal. If the Pats tie them then it will be a collective meltdown of epic proportions.