Hindsight is 20-20 if you have perfect, uncorrected vision in the back of your head.
If you do, there is very little chance you will suffer a surprise attack from a tiger.
Especially if you have other facial features back there, and are not just wearing glasses over your hair like cousin It.
Scratch that, we'd already established that your vision was perfect uncorrected.
Well, you could be wearing sunglasses.