PITTSBURGH -- Down on the first level of the CONSOL Energy Center, three fans wearing Penguins jerseys filed toward the exit. They did not look pleased. They were quiet as they shuffled down the hallway -- until one of them broke the silence with a single, loud, emphatic curse word.That happened mere moments after the Flyers capped an incredible comeback on Wednesday, overcoming a three-goal deficit to shock the Penguins -- and the crowd -- and win Game 1 of the Easter Conference Quarterfinals. Those three fans were clearly upset, and they werent alone.On the elevator from the press box down to the lower reaches of the arena, there was a mother who had two pre-teen children with her. The mom reminded her wee ones not to say anything to Dad about what happened. They nodded. Then she sighed out loud and asked the elevator operator to turn off the sound to a rather dour Penguins postgame show. When she was told that wasnt possible, she sighed again.It was natural enough that the people of Pittsburgh would have a visceral reaction to the heartbreaking and hard-to-fathom loss. The rivalry between the two teams has mushroomed into one of the best and most heated in sports. It means something out here -- just as it does back in Philly. As Kris Letangsaid (and Claude Giroux echoed) before the series began, the Penguins and Flyers hate each other -- which is why, he said, its always better when you beat the Flyers.That same principle works in reverse. Wins in the playoffs are hard to accumulate, making each victory feel like a combination of ecstasy and relief for the fan base. But when those wins come against your dastardly cross-state rivals, theres added satisfaction. Its elation super-charged by schadenfreude.Our friends over at The700Level.com have a great videoof Philadelphians reveling in the moment together and singing Mac Millers Knock Knock at Xfinity Live! shortly after the comeback was completed. That was the thrill of victory. Then one Flyers fan tweeted out a photo that captured the agony of defeat. The picture was posted along with three simple words: stunned Pens barAdding just a touch more insult to injury, Mac Miller is from the Burgh. Thats a little like Penguins fans celebrating a win over the Flyers by pumping The Roots' Rock You.If this isnt the most entertaining rivalry in Philadelphia right now, what is? Hating the Mets never goes out of style, but its a touch less enjoyable these days considering New Yorks other baseball team is in a state of disrepair. Disliking the Cowboys is a tradition, but there's somethingreflexive about it-- as though its expected of Philadelphia, and so Philadelphians comply. The Giants are natural villains, because of the geographic proximity and the success that makes Eagles fans envious. That has been a great rivalry for a long time.But this? This is as intense an interesting as all of those, and maybe more so. There are so many different story lines where the Penguins and Flyers are concerned, each serving toincrease the enmity between the organizations and their respective supporters.Sidney Crosby is a brilliant player, a singular talent, which makes him easy to love if youre from the Burgh and even easier to loathe if youre not. Pittsburgh fans boo Jaromir Jagr each time he touches the puck, even though theres a giant mural of him painted on the wall at the CONSOL Energy Center. The two coaches dont seem to like each other very much, and just to remind everyone of that fact, the Penguins played a video montage before Game 1 that featured the now (in)famous footage of Dan Bylsma and Peter Laviolette screaming at each other and doingtheir best John Calipari and John Chaney impersonations.Some Penguins fans took the extraordinary step of dressing in bear costumes after Ilya Bryzgalov said he isnt scared of anything -- except bears in the forest. And no one here can stand Phillys favorite antagonist -- which is fine by Scott Hartnell, because hes repeatedly said he doesnt dig Pittsburgh or the Penguins either.Asked whether the Penguins might be a little rattled, several Flyers answered diplomatically or talked around the question after Thursdays practice. But not Hartnell. He said a game like that can get in their heads, though he was quick to add that the Penguins have gotten the better of the Flyers in previous playoff meetings.The whole back-and-forth between the teams and the towns is fascinating. Fun, too. The other day, a Pittsburgh cab driver -- who was naturally wearing a Penguins hat and a Malkin jersey -- asked if I was in town for the series. I said yes. Then he asked if Im from Philly. I said yes again. Then he told me to get out. I think he was kidding, but luckily the cab was stopped and we were already at our destination.E-mail John Gonzalez at jgonzalez@comcastsportsnet.com