this is a good squat (video)

This is why I'm reluctant to do squats. Maybe perfect squats won't cause back or knee pain. But 90% of people can't do perfect squats, so they get problems. If you start to lift heavy, even ONE squat with bad form is enough to land you in the hospital. So why bother trying to do them if, regardless of how good you think you are, you're probably going to have some flaws in your form?