"Very difficult to understand American audience, what they like, what they don't like. Some movie I like very much, it doesn't work. Some movie I don't like, it gets big box office. Very difficult"

Jackie Chan is revealing his trouble in understanding the American audience. He is saying that it is hard to anticipate what they will like and what they will not like. He has actually experienced scenarios where he has liked a movie very much, but it has actually not achieved success, and other times he has actually not liked a movie, but it has actually been a big ticket office success. This unpredictability makes it really hard for him to comprehend the American audience. He is revealing his aggravation at not having the ability to forecast what the American audience will like and what they will not like. This quote reveals that Jackie Chan is a simple artist who is willing to accept that he does not constantly comprehend the American audience. He is open to finding out more about them and their choices in order to much better serve them.