The first time I had dim sum, I thought, "wow, what an inefficient way to serve food." It just didn't make sense. Instead of ordering what you wanted, you were forced to eat whatever they had. And since I came at a non-peak hour, the pickings were slim.
I've since learned that those problems don't happen at better dim sum places.
Recently, I've been going to Ming's in Palo Alto:
http://www.mings.com/