I get mad when I am passed by a biker on a hill but the day I get passed by a walker, I think my head will explode!
I can't run because of back issues but one of my workouts at the gym is to get on the treadmill, set it at 15 degree incline and 3 to 3.5 mph and walk as long as I can. It is a heck of a work out for me.