This is probably a dumb and petty thing to care about, but I've always had the opinion that distance runners overdo it on their cooldown runs after workouts/races. Specifically when people treat a cooldown as an opportunity to "tack on more mileage" and not to actually relax the legs and help recovery. Seriously, how many miles does it take to actually cooldown? 1, MAYBE 2? It's definitely not the 3-4 miles that some runners do. I feel like that time running on tired legs would be better spent recovering, and if you feel good enough to be running around for 20-30 minutes after a workout you probably didn't work out hard enough. Those extra miles really aren't of good enough quality/quantity to be worth the extra damage done on the legs.