Conversation:

For Christmas I would like a eye grafted onto my right index finger for all those times I need to find beer money down the side of the sofa. If it could come with a spotlight on the end of my thumb, so much the better... it could be useful for those one-night stands when you need to find those interesting little places in a hurry.

Then there is a book on one hundred curry recipes for turkey that would be handy...

But imagine how strange it would be if you then pointed your right finger at your left eye.

Or if you tried to put in a contact lens with that hand.