I used to be of the mind that as the tank I set the pace and what I say goes, but guess I just don't see any point anymore in stonewalling and trying to get my own way when the other three people are in agreement. When I queue as tank I'm prepared to either speed run or take it slow depending on party composition, gear, and what people want. If the other three players want a speed run, I'm not going to pull three mobs at a time when I know I'm perfectly capable of tanking everything up to the first boss in a huge pile for those two pyromaniacs black mages. When I queue as healer, I'm prepared to either heal a speed run or DPS my tail off on small pulls.

You're all there for the same reason - to complete the duty. Nobody really expects anything more than to finish it as efficiently as possible. So if you find yourself in a party wanting a speed run, why not go along and try to have fun with it? Stepping outside your comfort zone once in awhile can only make you a better player.