Like I said, It's roulette you ask for then roulette you will get, simple enough isn't it? If you want to do many dungeon they can have you specify 5 dungeons/trial/whatever you want to run. Want that myth/sold? How about multiple 15 mins BF HM speed run with your friend? It's way faster than get a roulette and leave then got a locked out.

Many times I run Amdapor city or such just for fun or for gear that doesn't matter, so, If anything please at least try to complete it, try tell someone what you want them to do If you tried and quit because of you can't go with the group by any reasons even it's still bad thing to do but it's better than leave without try. The problems are there for you to try to solve not to run away.

I do aware that some people just cannot do what they are told to do because there real life problem, connection problem, there are idiot, trolling, lack of experience, etc. It will be the test for your tolerate threshold. I agreed that in some case it cannot be solved or cannot complete a run in the dungeon, if it the case you have to leave with a good reason, but not before you try!

I do play DPS for sometime and I gonna repeat I never saw any class other than tank leave instantly after the dungeon start (before duty commence), leaving the clock ticking inside the dungeon maybe 30-45 mins before we get a new tank.