Why does Cameron wear suspenders and a belt? To illustrate how uptight and insecure he is.
Cameron stares at a pointilist painting. The camera zooms in closer and closer until the subject matter becomes incomprehensible. Cameron is fixated with it because he is afraid that, just like the painting, the more you look at him, the less you see. He is nothing.
Cameron wears a Detroit Red Wings jersey in Chicago, the land of their bitter rivals. This highlights his alientation to his surroundings.