That said, I'm never gonna be "hardcore," and frankly I'm glad. There is a line between "delightfully geeky" and "obnoxiously nerdy" that gets crossed somewhere in there, and if you find yourself inspecting people to audit their gear, or talking smack about how pathetic people are for enjoying roleplay at the Prancing Pony instead of farming Teh Grindy Hardmodes, you've passed it, in my opinion.
I can't speak to other MMOs, 'cause I haven't really played any others for more than a weekend, but in LotRO at least, the "hard mode" of any instance is usually the least fun way to play it anyway. Moria is especially bad for this, where the HMs are based on things like "get to the main boss as fast as possible, bypassing as much of the instance as you can to get there." Grand Stairs is the poster child for this: "quest mode" is 2-3 hours of cool, varied fun against multiple bosses with very different strategies. "Hard mode" is "run to the one guy at the end -- GO!" Screw that. But nobody wants to run quest mode, because HM has bigger rewards. So you get the best stuff by bypassing most of the content. What the heck kind of sense does that make?
I also just don't perform well in zerg mode; in an instance where we can relax, work our way through it, and stop to enjoy the scenery every once in a while, I have a lot more fun and I do a much better job. If I'm running around trying to pick up aggro all over the place because the designated leader is already off at the next pull before we've even finished looting the bodies, I quickly lose my focus and begin to wonder why I'm even bothering to play. I want to see the instance and get the entertainment value out of it that I paid for. Why go out of my way to skip as much of it as possible? What's the point of that?
Anyway, that's my rant for now. And honestly, looking back at it, it's mostly a reaction to a handful of specific people that maybe I just need to avoid when I'm grouping, because experience has shown that when they're not in the group, I enjoy grouping a lot more.