I've written before on here about being the "other guy:" being the opposition fan in the building. If you're one of a mob, it's easy to handle, but if you're one of the few, you know that you stick out a little more. Some people make up for being one of the few by being horribly obnoxious, and others just sit there, mute. To me, taking the latter approach defeats the reason that you're at the game to begin with, but if you try to act like an army of 100 fans all by yourself, people are going to absolutely hate you. You run the risk of associating that behavior with all of the fans of your team. It's a fine trapeze act when you're cheering for your Blues in another barn.
Some teams' fans don't walk that high-wire well. Detroit fans get superior and complain when the home team's fans are yelling too loudly when their team scores (no, really, had Detroit fans in front of me earlier this season do that), and they'll shoot you nasty looks as they leave five minutes early because their team's getting their ass kicked. Bandwagon Chicago fans in their shiny new Kane jerseys will heckle other fans like the tables are turned and the game's being played in the United Center. Buffalo Sabres road fans invade your arena like a plague, get blitzed, and try to pick a fight with seven year old kids (I've seen it happen), throw beer on other fans, yell obscenities, and generally act like cretins. There are just some fans that you don't want in your building.
This isn't meant to knock fanbases that travel well - Penguins fans can show up en masse to cheer their team, but my experiences with them have all been really solid. Flyers fans have a reputation, but recently they seem to have mellowed - of course, anyone who buys me a beer to apologize for the ass kicking their team is laying on mine, I'm ok with. Maple Leaf fans are generally pretty cool people, as are Sens fans. Even Bruins fans can be fun if you really start to get them going and ticked off during the game - I appreciate someone being able to give as good as they get.
Honestly, the best experience I've had with opposing fans has been with Nashville Predator fans. They sit in loud little clumps behind their team's attack twice side and yell jeers at the goalie, especially after one of their guys score, but they're not "look at me!" about it. They just seem to do it because that's what they do at home. The last time they were down here, and lost, the fans in my section shook all of our hands and congratulated us on a good game. It was just... weird. But in a good way.
Are there any fans that you see show up at Scottrade and you're ok with it? You're not necessarily happy that every person there isn't wearing Bluenote blue, but fans that you know that you can have fun with, tease, and still leave on good terms? Fans that you don't feel the urge to throw over upper-deck railings? Or even fanbases who, when they cheer their own team, you don't feel the urge to dump a $9 beer on?