The chief says, "what makes people so impatient is what I cant figure; all the guy has to do is wait." What does this mean?

He understands the concept of patience in ways that most people do not; he has been in a situation throughout much of his life where "waiting" was the norm. In the Army he certainly would have had to wait a great deal. In the hospital, the waiting is just another part of the "hurry up and wait" mentality Bromden has already been subject to.