What is the appropriate reaction when you encounter a snake in the wild?

Actually even many venom snakes' first reaction when being approached by a human or another large animal would be escape rather than strike. Some will stand their ground and try to scare you away. Their venom don't come cheap, and they want to save it for the hunt instead of wasting it on something they can't eat.

So according to you, slowly backing away is the right thing to do. What if the snake is already on the top of you? Lets say you are camping and taking a nap. You wake up to a snake passing on your legs.