I took the day off work today because it's my son's birthday and some of our adult children are in town to help celebrate. So this morning my wife and I had the opportunity to make our bed together. (Usually we follow the "last one out" rule -- the last one out of the bed makes it. On my work days, my wife is usually last one out, unless she can't sleep. On sleep-in days, I am usually the last one out.)
As we tugged at the sheet and bedspread to get them even, we laughed as we pulled them out of one another's hands until they were finally aligned. It would have been just as easy to be annoyed at the other's tugging, but we had a common goal, and we were well rested enough to laugh rather than scowl.
A valuable lesson in marriage: common goals and a propensity to laugh rather than scowl can make all the difference.