Originally posted by cxdoo I see why this would annoy you, it happened to me a couple of times too, but not lately. I usually look for biggest, most contrasty surface in the plane I want in focus, focus and recompose.
I have more problems with inappropriate shutter speed (too low) when in Av mode so I tend to use TAv when I expect motion blur to be a problem.
It wouldn't just annoy me, it also annoys the people I take the photo of. They have to stand there for a minute while my camera is trying to focus on everything but the motive. Often times the most contrast is for example the glasses of someone, so I focus on that, but the camera picks the background instead. I can understand the purpose of a bit larger focusing points... you don't have to point so accurate. By having several, say, 20 small AF points in the center covering the area that is usually covered by the K-5 AF center point, and having each of them be able to light up individually, I could instantly see if the camera has picked the background instead, and focus again. I'd be very happy with that. Besides, by having several AF points it could pick the closest one it can lock on.
Another thing 200/400 AF points on a camera with live view enable is for the camera to focus on exactly the eyes of a motive. And to take a depth map of the whole photo... so it can focus and set aperture exactly so that from front to back everything is in focus. There are many possibilities, some of them surely not yet realized with these new cameras.
@normhead: Why don't you use the AF button to focus? That's what I usually do... focus once, and then shoot as long as the motive doesn't change the distance to the camera without focusing again (especially if I have verified that it is indeed in focus).