He's a wacko.
I still love him as an actor though.
One comment was that the movie he did with Nicole Kidman Eyes Wide Shut was related to Scientology, because of the cultish aspects: High profile people, including top celebrities who secretly engage in cult rituals. There were also stories about orgies in Scientology, but I doubt whether they were widespread.
I also saw a clip a few years ago on youtube where he was wearing jeans and talking about himself in a straightforward way. It appeared to be a scene from a movie. Does anyone remember this?
I don't remember it from Vanilla Sky, but the scene reminds me of something more from that movie or from Magnolia than other movies of his I saw.
I remember thinking that it's as if he was describing his experience or personality in relation to scientology and that made it humorous. But of course I doubt he would make a critical portrayal like that knowingly in a movie.