Yeah issues abound with DF
The biggest trouble is that DDs are a dime a dozen, but healers and tanks, not so much. Because of this, people will queue as a healer or tank just to get a duty in shorter time so they can get what they want and split. Happened a couple of times with some folks. It's annoying and completely sours the vibe of the community. There's nothing wrong with gunning for a specific piece of gear or item, but at least see the quest through to the finish. You have to consider that there are others in there with you.
And also, for the speed-running, cutscene complainers, you SHOULD run with a preset group. Think about it: you want a reliable speed-run through the dungeon, which means you're going to want a setup that can best deliver that. Grouping with random people will likely not give you that. In that regard, DF is a bad option for a speed-run. Find a static team and smash CM or AK for your tomestones/loot. You get your speed-run, others get their immersion, everybody wins.