It´s great to have a main character with a defective personality that initially tend to be bad, because through the film we can see how he loses power, loved ones, but still manages to become a better person at the end. For me the best part about the argument and Hou Jie is that the film shows the awareness of guilt and also redemption.
It´s a beautiful movie and has this kind of logically sad endings, so is perfectly understandable why things ended like that, no frustrations.
Other strong points are: Great fight scenes, well-paced development, the beautiful final song, Andy Lau, and of course Jacky Chan