Because everything, including appreciation, is normally distributed. In this case these elements share a requirement for other qualities, which are also normall

Because everything, including appreciation, is normally distributed. In this case these elements share a requirement for other qualities, which are also normally distributed. Most (in the middle of the distribution) will hate a puzzle that is too difficult and it will be discarded with disgust. Some (on the left of the distribution) do not understand that it is a puzzle. Yet others (on the right of the distribution) become fascinated and may choose to dwell with the difficult puzzle over a lifetime.