The phrase that has always bugged me is "behind one's back". You know. "They're talking about me behind my back", and so on.
Behind my back.
As opposed to what?
In front of my back?
(Well, yes, "to my face", but what kind of opposite is that? Lame.)
So, if any given outside surface is pointing outwards, then the surface of my back would be pointing outwards as well, and the orientation of the normal vector for my back is opposite to the orientation of my nose, anything going on behind me (if I define the orientation of "me" as equal to the orientation of my face), is actually in front of my back. Meaning, anything going on behind me would be going on in front of my back. That, in turn, means that when someone is doing things behind your back (
), he's actually doing the thing in your face (
). The fact that the phrase literally meaning "in front of you" actually means you're oblivious to the doings can only be an indication of your general ignorance or not being able to get the hint if it pokes you in the butt.
(Double entendre notwithstanding.)
Behind my back.
As opposed to what?
In front of my back?
(Well, yes, "to my face", but what kind of opposite is that? Lame.)
So, if any given outside surface is pointing outwards, then the surface of my back would be pointing outwards as well, and the orientation of the normal vector for my back is opposite to the orientation of my nose, anything going on behind me (if I define the orientation of "me" as equal to the orientation of my face), is actually in front of my back. Meaning, anything going on behind me would be going on in front of my back. That, in turn, means that when someone is doing things behind your back (
(Double entendre notwithstanding.)