I think the biggest problem is people running with a heel-first contact to the ground because thick shoes make that feel comfortable and effortless despite the

I think the biggest problem is people running with a heel-first contact to the ground because thick shoes make that feel comfortable and effortless despite the human foot and legs never having evolved to take such hard impacts. Take off someone's shoes and tell them to run on any surface and 9/10 will automatically start running on their toes to reduce foot and leg impact. Heel striking bare foot is not pleasant. The only problem is if someone never runs on their toes and suddenly do run on their toes because they get told it is better, they will quickly tire their feet and calves out and assume the person was full of shit because they ran far longer and easier heel striking because that is what they are use to and built up endurance to do. You can often tell if someone exclusively heel strikes and doesn't stand or walk or run on their toes at all because they will have super thin calves. You can see it in some people in how they place their foot on bike pedals too, toe runners pedal with their toes, exclusive heel strikers pedal much closer to their heel.