Ok here is a good one for you all. A nice little optical illusion. Check out the faces below. It is obviously Mr Angry on the left and Mrs Calm on the right. Now as you back up from your monitor you will notice them switch places (at a couple of metres). There is no trick, it is not an animated picture, just plain old optics messing with your head.
It makes you realise that we all see things in a different light, yet in similar ways. Get 10 people to describe an accident and they will all describe different things. Not only that but the memory that records these events for us is prone to failure or re-configuring as time passes or we mature mentally.
possibly credited to: Phillippe G. Schyns and Aude Oliva of the Univ. of Glasgow.