"Why does everyone keep their foot on the brake even when stopped for minutes! I have a working hand/parking brake in my car."
Operating the hand/parking brake, mean you have to put down your cellphone for a fjew milliseconds.
... or god forbid, actually use your left foot for something (to engage/disengage the parking brake)
a startling number of people in the states seem to think that it's truly an "emergency brake" or just e-brake and that you should never use it outside an emergency. it never occurs to them to use it for any other purpose than if your hydraulic brakes fail. personally i have in fact used it for that very purpose (a braided stainless steel brake line had been installed improperly and sprung a leak, losing all fluid for the rear brakes and making the pedal drop to the floor) but then since my car is a manual (an extreme rarity in the states) for me, it's primarily a parking brake (and thankfully when my brakes failed, i could downshift to slow down, too).
that said, when driving an automatic, i don't use the parking brake except when parking on a hill, or when doing maintenance/repairs in the driveway. if i'm sitting at a red light it's not like it's difficult to continue holding the brake. in my manual shift car i'll let off the brake and clutch with it in neutral at a red light, and if the ground isn't level i'll set the handbrake. in my wife's automatic, if the light is very long, there's a train, or if traffic is just THAT bad, i'll simply put it in park and let off the brake.
even though i've been driving stick almost my entire driving career, it's still amusing when i let off the brake and the person behinds me starts to go, as if the light had turned green. nobody's ever hit me, but there have been a few close ones...