They say that if you put a frog into a pot of boiling water, it will leap right out to escape the danger. But, if you put a frog into a pot filled with water that is cool and pleasant, and then you gradually heat the kettle until it starts boiling, the frog will be unaware of the threat until it is too late. This parable is often used to illustrate how humans have to be careful to watch slowly changing trends in their surroundings, such as in a marriage,...