There is a difference between learning the fights, and just not understanding mechanics in general. Unfortunately there are those who don't understand you can't stand in the green puddle, or that you shouldn't stand in the red cone. I rarely leave a duty, but if it's obvious that you lack the skills to understand anything mechanically then I will leave to avoid wasting my time. I work quite a bit and so the free time I do get to play the game, I want to spend it getting things done and not dying repeatedly because I have half a party of derps that just aren't ever going to get it right.
