Normally punching is something we all take for granted. We all think we know how to punch. When we put a set of rubber cords behind you and ask you to punch as in this video, you will see that the direction of the punch and the alignment of all the body parts involved are not that easy to control. When not done correctly, you can see that you punch yourself off balance, instead of punching the person in front of you. You will realize that punching correctly does not make you look like you are punching.
You can purchase the full video here: http://practicalmethod.com/2012/02/germany-2011-private-workshop-6-online-video-trailer/