Why diving for a coin is more difficult than it seems to be from the side of the pool?

When light is refracted in water, the image becomes slanted in appearance to the human eye. The human eye is the most easily decieved sense of the 5 senses. Once you are in the water, open your eyes to see where exactly the coin is. Do not retrieve the coin, because this will bring bad luck, and once a coin is tossed in from a wish, it cannot be fetched. If the cycle is disrupted between the wisher and the gods, you will be put under a 75 year curse. So do not dive for the coin at all.