Have you ever wondered why some outlets are upside-down? It's because they're supposed to be installed that way. Most outlets are actually installed incorrectly. They're notsupposed to look like little faces. Why? Because the small hole that is the "mouth" if the little face is the ground wire, and it's much safer to have that on the top. If the other two things were on top and the outer plate slid down and touched the hot and neutral wires, the circuit would short and you would have a problem.
Also, you might notice that when you plug in something that has the third prong, like a vacuum cleaner, it feels like you have to turn the plug upside down to get it in the outlet. This is why. I think electricians and owners alike enjoy looking at the faces of outlets, so I doubt this practice will change anytime soon.