Hitting the floor or shouting KATZ is only a technique. Sometimes using this technique is necessary, sometimes it's not necessary. It's a kind of sickness. Sometimes people are attached to a good answer. That is not correct kong-an practice.
Correct practice is necessary.
That means throwing away our attachments to our conditions, opinions, and situations. American mind is intellectual, very analytical. The intellectual mind cannot pass kong-ans. Correct kong-an practice means your mind becomes very simple. Then practicing kong-ans is no problem.