The minor nature of its goals is the whole point. It is not meant to do what we want because it empathizes with our values and is friendly, but because the thing we actually want it to do really is the best way to accomplish the goals we gave it. Also I would not consider making a cheese cake to be a trivial goal for an AI, there is certainly more to it then the difficult task of distinguishing a spoon from a fork, so this is surely more than just an "intelligent rock".
At the recent London meet-up someone (I'm afraid I can't remember who) suggested that one might be able to solve the Friendly AI problem by building an AI whose concerns are limited to some small geographical area, and which doesn't give two hoots about what happens outside that area. Cipergoth pointed out that this would probably result in the AI converting the rest of the universe into a factory to make its small area more awesome. In the process, he mentioned that you can make a "fun game" out of figuring out ways in which proposed utility functions for Friendly AIs can go horribly wrong. I propose that we play.
Here's the game: reply to this post with proposed utility functions, stated as formally or, at least, as accurately as you can manage; follow-up comments explain why a super-human intelligence built with that particular utility function would do things that turn out to be hideously undesirable.
There are three reasons I suggest playing this game. In descending order of importance, they are: