You know what they say, big fingers, big...aggression?
I stumbled upon this article right here that says "Fingers May Point to Male Aggression." Basically what its saying is that a short index finger in comparison to the ring finger is an indication of aggressive behavior. For the record, my index finger is pretty much the same size as my ring finger. That just proves that I'm a lover not a fighter (but if you cross me you might just find a 16 inch screwdriver lodged in your forehead).