Mahjong
Nobody knows what they want , they just want someone to tell them what to want.
That's the main premise of the film , transactional relationships rule the world , money is the root of all problems and such and such , in the pursuit of wealth you are willing to do terrible things , use your friend as some kind of sex lure , the other as a fake interpreter , the other as a mystic , the list goes on .
I love how Edward Yang conveys this through the lighting and camera angles , say when we saw Marthe in the police station , the real relationship was in the foreground full of emotion and natural light while the other was in the background in what looked to be fluorescent light , or in the pivotal scene of the film with Red Fish , him just realizing what he had done the lighting was going crazy flashing reds , blues , yellows in the middle of the night perfectly portraying his confusion and frustration.
At first the film might seem a bit disconected and confusing but trust me the message is conveyed as we go along reaching the perfect finale ( and yes it was in the foreground ;)