Mirror Mirror

I love how, when you've finished getting your hair cut, the hairdresser holds a mirror up to show you the back of your head. The problem with this is that at any given time, I have no idea what the back of my head looks like, so I'm pretty clueless as to whether what I'm being shown is actually an improvement.

I'm pretty sure that when I say "That's great!" as I invariably do, it's either because I never cease to be amazed by the simplicity of the two-mirror trick, or, much worse, it could be because I'm just very excited to be seeing the back of my head again...