Dunno about you guys but where I live it can get up to 101 degrees with 99% humidity here. In case you haven't lived through that, just trust me: it's a special kind of heat. One you can feel in your lungs.
I don't drive much but I damn sure don't go anywhere during the summer without my A/C on the "max" setting. But believe it or not, I've gotten in the car with people around here that still refuse to run their A/C. What good is saving a few pennies on gas by not running the A/C when you have to steam-clean your car because it smells like smelly, sweaty butt? Not much, if you ask me.