Whenever I go canoeing, I see couples arguing as they unintentionally run aground or get hung up on a rock. Canoeing looks easier than it is, and that may be why it quickly brings couples to the brink of battle. Arguments occur far less frequently when I meet a couple for drinks or go to their home for dinner, and it isn’t just because they are trying to be on their best behavior (after all, why wouldn’t a couple also try to be on good behavior on the river?). I think it has to do with the well-established patterns of behavior people have for their normal, day-to-day activities (arguing vehemently at the table in front of strangers is pretty much a no-no in most families).
But when you’re on a river, the situation is largely new. There isn’t a clear protocol. The river is unpredictable, and canoes tend to drift and turn in ways you don’t anticipate. (This situation is very much like life, which is full of new and surprising stresses and roadblocks.) There’s also a fuzzy kind of division of labor between the front and back (or bow and stern, if you want to be technical). This context offers plenty of opportunities to establish and observe fresh patterns of behavior.