I'm not entirely sure why I actually enjoy the wait for a DPS slot in a random dungeon. I used to run as a tank, but frankly, I can't run more than two dungeons that way because the queue keeps instantly popping and I keep clicking and next thing I know an entire day is gone and my mouth is dry and I have no idea where I am. Queuing up as a tank or healer (not that I currently heal all that much) is like sitting down with an entire bag of peanut butter cups. Yes, I will eat them all. Yes, they are delicious. And yes, I'm gonna get a stomach ache.
On the other hand, the DPS queue, while it means I'll get a lot fewer points, tends to be much more digestible for me. Run a dungeon, queue up for the next one, go get a drink (maybe use the bathroom) and settle down for a nice 10- to 15-minute piece of me time.
I know some folks really hate the queue. Some even heal or tank when they don't want to or know how to, just to avoid the wait times. Me, I really like those periods of lull between the action. How about you? Do you always have to be doing, or do you take some time and not do anything?