In Korea, the director has the final word. If the director makes a decision, that decision is final. In Hollywood, every decision needs to go through the producer, the studio, and sometimes even the main actor. There is a certain procedure that needs to be followed.
In Korea, the director is on top, and the power flows down vertically. On the set, I love to come up with ideas on the spot. But in Hollywood, if I were to come up with a certain idea on set, the idea had to be taken to all these different people who had to agree.
One quality that a director needs to acquire in Hollywood is to understand the system and figure out how to work within the system to express one's own ideas.