The biggest hindrance I face when teaching is the defense of falling.
If you do not know how to fall properly, most of the techniques in this video will take the attacker out of the fight. The ground hurts. When you are thrown into the ground hard, it breaks you up or steals your wind.
Falling is an art unto itself - defensive. If a good fighter has you and you resist when you should go with his energy - you will break.
Yes, there is a bigger message there. I'll let you work it out.