I started doing this when I was a little kid.  There was this comic book, and the bad guy had one side of his face evil and one side was good.  I took the pictures of him and put them up to a mirror so I could see what his face would look like if both sides were evil, and if both sides were good.  That got me started doing the same thing to other comic book characters, then to people in magazines and newspapers.  

The results can be startling.  Very distinct and often opposing personalities appear;  in fact, I think the faces that appear say a lot about hidden personality elements of the person you're looking at.

No, really.  The left brain hemisphere controls the left side of the face and the right side of the body, and vice versa.  It's known that the brain hemispheres are fundamentally at odds, controlling different aspects of personality;  I think this little game reveals the split in personality in all of us.  Try this with a picture of a really 'saintly', enlightened type, a monk or something;  they show little difference at all.  Powerful, driven people tend, in my opinion, to show radical differences.

Well, one can take it or leave it, I guess.

The results are often freakish, and this might seem arbitrary and meaningless.  For instance, the neck will often be very thick on one side, and thin on the other, which is simply because the head is tilted slightly.  On the other hand, this will often be very consistent in different pictures.  I've tried to illustrate this with the pictures of Al Gore;  and I'll try to do the same thing with the other people I 'do'.

It's damned difficult to get a good, full-frontal face shot of Al Gore.

Somehow, I suppose I shouldn't find that surprising.