Have you noticed that you can twiddle ONLY your thumbs? That's a point against thumbs actually, not for it, for the simple reason that every single other finger has a use... A friend and I were twiddling our thumbs when the conversation came up... we noticed that the index finger is used to point at things and remove things stuck in various body orifices (other's body orifices in some seriously nonfeminist films), You contemplate the uses of the middle finger, and you will probably get one, the ring finger... well, is for the ring... and it might seem stupid and insignificant, but what the hell, the ring signifies the most important thing in most people's lives, so... I came up with the little finger, and was pretty sure it was as useless as the thumb, but my friend rattles of a list making it THE MOST USEFUL FINGER OF ALL... to say katti, to seal the most solemn swear, to seal a bet, to show that you have to urinate without words, AND to pick things out from smaller body orifices.
That leaves the thumb, in his words "bura lagega karke twiddling ka kaam diya"... nice myth about the opposable thumb being the most useful finger of all and crap like that, I am not even using it to type.
The deeper insight about the whole thing is however, the ring finger again... think what the ring finger represents ok... now, it is between the middle finger and the little finger, and think what THEY represent in turn right? - now comes the really cool part, the ring finger is the weakest - because it shares a flexor muscle with the middle finger and the little finger. Now thats a laugh.