A filmmaker like Wong Kar Wai is a known quantity. He has never surprised me and I doubt he ever will. So, yeah, I have faith that his movies will all be very similar in terms of style and tone. And that particular style and tone work for me. Even when the movie isn't as good ("My Blueberry Nights"), I still appreciate those aspects of it. His style and tone don't work for everyone.
You, BoobyTrap, yourself have noted on a number of occasions that certain soundtrack composers have their own style. The majority of Hans Zimmer or Danny Elfman's work sound like Hans Zimmer or Danny Elfman. Occasionally they slip up and let out with a Pearl Harbor or a The Kingdom, but for the most part you know what you're getting when you put one of their discs in your CD player.
Most filmmakers are no different.
My faith is not blind. Edgar Wright has shown me that he is worth the faith I put in him. The same can be said for most directors/actors/musicians/writers/artists/etc whose work I will support regardless of what it is or what it's about. It's not foolproof and I do find myself disappointed occasionally, but those instances are rare enough that I am perfectly comfortable with my way of doing things.