It's a shame humans don't have twelve fingers instead of ten, because there would be hundreds more finger combinations for offensive hand gestures. Six fingers per hand seems ideal for this. Any more, and after a while diminishing marginal returns kicks in and the effectiveness of the gesture decreases ("Wait, did he just hold up the fourth and eighth finger, or was it the seventh and eleventh? I'm either a pregnant cow or a vulva with herpes...but either way I'm offended..."), and also it would make certain human activities, ahem, difficult.
But with the hand gestures we Americans have, we seem to get by okay. Of course, there's nothing like throwing up a palm in Greece or flashing the peace sign in England, but the good old middle finger usually does the trick when you want to insult a biker outside a seedy redneck bar in the Ozarks. The middle finger is America's premier offensive symbol: simple, strongly erect, relatively easy to negotiate despite the stubborn ring finger phalanges, sexually suggestive...it's everything an American desires in a hand gesture.
Recently, though, the "up yours" attitude of the middle finger has been supplanted by the much more metaphorically complex "shocker" gesture, which is not to be confused with the Pitchfork, the Arizona State official hand gesture (which magically looks exactly the same!). It's amazing to me how diverse our 43rd President George Walker Bush is in the bedroom, because not only does he endorse the "two in the pink, one in the stink" mentality:
But he also does some crap I don't even want to think about:
Stay strong, Laura. We need you until January 20th, 2009.