Have you ever read something on the forums or on a blog about a new and disturbing trend emerging in pugs and thought, "wow, that sounds so stupid, I'm glad nobody is doing that in my guild/on my server/in my battlegroup"? And then, as soon as you queued up for your next random dungeon, someone actually did that very same thing? I always find it a bit unsettling that someone might have read the same articles as me and actually came to the opposite conclusion, going "oh, that's awesome, I'll have to try that on my next run".
Case in point: skipping bosses in heroics. For a few weeks after the dungeon finder's introduction, all the runs I got into were still full clears. Then it slowly started with things like people skipping Amanitar in Old Kingdom, then Jedoga Shadowseeker too. Then people wanted to go straight to the Tribunal of Ages in Halls of Stone without taking a detour to Crystallus and the Maiden of Grief. Then my parties started to ignore Eck in Gundrak. And last night it reached an all-time low for me when I got into an Utgarde Pinnacle run where the tank didn't want to kill Svala Sorrowgrave.
Now, part of what made that incident so annoying was simply the tank being a twit, as his response to people saying that they did in fact want to kill her was, "I'm the tank, I decide". I tried to type out a reply to politely express that I thought this was rather inconsiderate, but before I even had time to do that the tank had rushed ahead, pulled multiple packs at once and wiped the group. It shouldn't surprise anyone that I left that party...
But that aside, skipping Svala would have bugged me even if it had been asked for in a polite way. It's not that I expect every instance to be cleared down to the very last mob, though I think people have become ridiculously spoiled in that regard. It's one thing to skip a few bosses in BRD, it's another to argue that Amanitar is "totally out of the way" because there are three trash mobs between him and your party. Seriously.
Weirdly enough, I think what bothers me the most about boss-skipping like that is how it breaks my immersion. I hated the "ledge strat" in Halls of Reflection too, because it just felt ridiculous to stand off to the side while the Lich King walked past, completely ignoring us. I know WoW heroics aren't hugely immersive anymore to begin with, but players making a point of destroying even the last remnants of make-believe annoy me nonetheless. And yes, that includes running right past a val'kyr that we just watched get empowered by the Lich King just because you want your instance run to be two minutes shorter. Bypassing bosses that are down a tunnel somewhere bothers me less, because I don't find the idea of our party not exploring every nook and cranny of the instance that immersion-breaking.
Emblems actually don't come into it for me. Some of my alts can still use triumph, some don't... but that's not the point! It may be hard to believe, but I actually still enjoy running instances for the sake of running them. Getting rewards is nice, but they aren't the point. When I don't fancy a heroic, then I skip it that day, so what if I miss out on frost emblems? I play to have fun, not primarily to earn virtual currency; and I really wish more people would remind themselves of that fact, as I'm getting increasingly tired of the "I just want my frost even though I hate instancing" mindset. It sounds a lot like the gold buyer's mantra really: I want to be able to buy all this stuff in the game, but I don't actually want to play it!
Really, if you're not having fun doing something in the game... don't do it! Or rather, I'm obviously not going to stop you if you want to get some obscure old world reputation to exalted while all the time moaning about how much you hate it, because it doesn't really affect me. But please stop trying to ruin my fun by participating in group activities that you hate and making everyone else in the group miserable by skipping half of the fun and having a crappy attitude.