Well, it doesn't necessarily need to be dumb for you to complain about it, so I guess this thread covers a wider range of things.
As for me, I totally agree with mugenbenoit on that many times the directors don't make full use of the actresses', uhm, let's say, arsenal. For example, in many of the female teacher films that focus on legs/butt the actress only shows her boobs in the last scene, and in other similar films even if they take it out the camera doesn't take it into consideration and you can not see it that well whereas having it out there would really make the scene that much more visually appealing.
But my biggest complaint would be those unfortunate instances where an actress that you like doesn't do the kind of genres that you like - or at least not often enough.