I whilst ago, whilst waiting in queue to board a commuter train, I had the urge to reach down and feel a stranger's rear MTB tire for proper air pressure. I was almost sure it contained less than the higher range of pressure that decreases rolling resistance and augments momentum.
A few nights ago at work, I could not resist, and casually grabbed and squeezed several front and rear tires of bikes locked on the racks. It's perplexing that quite a few tires were almost flat, as if these unknown co-workers had won the lottery and abandoned their jobs, and single track machines, or, decided to drive after a discouraging, under-inflated ride to work misrepresented the capability and joy of the machine. Another brick in the horizontal wall.
Here is a link to a previous Bike Forums link about air pressure, with some humor: