When married couples are asked to name their biggest problem, most say it is poor communication. Good communication skills pull a couple together, while poor skills push the two apart. Of course, communication between any two people can be challenging. The reason why it's harder between spouses has as much to do with nature as nurture; meaning differences between the sexes that are both biological and cultural in origin. It's these differences that complicate matters and explain (in part) why the thing that should get simpler over time — communication between a man and a woman who spend the greater part of their days and nights together — needs to be constantly relearned, practiced, and refined for the marriage to stay strong.