Honestly, between you and I, pilots do amazing things.
However, there's honestly very little excuse for sitting on an air conditionless airplane. If the APU is broken, there's ground air. If there's no ground air, there's an air cart. If there's no air cart, get a "Lewinsky" and run the packs off of it. If there's no APU, no ground air and no "Lewinsky" available, deplane the passengers until the gate hold (if any) is a lot closer.
Plus, talk to the people. They really have no idea what's going on behind the scenes at all. If it's gone absolutely pear-shaped, tell 'em!
Seriously! Personally, if I'm sitting on a blistering aircraft in the middle of summer for an hour and my only respite is buying a $2 coke once we're finally in the air, all that wonderment of the crew not killing me, traveling at 500 mph and landing on a narrow piece of runway thousands of miles away isn't going to amount to a hill of beans.
Worst comes to worst, we've gone from near anarchy to everyone thinking we're the shiznit just with a craftily-worded PA.
I dunno, that's just how I roll.