"If we stop now, it'll fester"

The fear that keeps you on the sofa is of what the row will be in the morning if you leave it. Bigger. Set. Harder. A night's growth on it.

Matthew Walker and Els van der Helm, in a 2009 review, drew together research on what sleep does to emotion. Their model, built from a wide range of studies, is that sleep isn't a pause in emotional life but a stage of it. During sleep, and particularly during the dreaming phase, the brain reprocesses the emotional experiences of the day, and the effect of that reprocessing is to bring the next day's emotional reactivity back into range. What was raw in the evening is, after a night's sleep, still remembered but less charged. They called the paper "Overnight therapy?", with the question mark, and I'd keep the question mark. It's a model, and the notes say so. But the direction is the opposite of festering. Sleep is where the row gets worked on, by a process that runs whether or not you've settled anything, and the morning version is the product.

Bread left to prove overnight is a fair comparison for two sentences. It's changed by morning, and the change is the point, and nobody stands over it at one a.m. to stop it rising.

Now compare the two mornings. In one, you settled it at one, in the sense that one of you gave in and you went up, and you wake having slept five hours with a settlement you can't quite remember agreeing to and a sentence from half past twelve still in the room. In the other, you called a truce at half past ten, went to bed cross, slept seven hours, and wake with the row processed, smaller, and a time at eight to finish it with the two of you who are actually capable of finishing it. The festering belief predicts the second morning is worse. In my observation, and this is observation and not the review's finding, it's the first that's worse, because it has the night's damage in it and the second doesn't.

What festers is a row that's left with no time to come back to, and that's chapter 17. A row left overnight with a resume time isn't left. It's parked, and parked things don't grow. They wait.