"One slip and it's over"

The drop is usually a single day. You missed the run, or you ate the thing, or you didn't open the document. And then something happens that isn't in the missed day at all. You decide the whole thing is over. It wasn't one Tuesday. It was the wish, and the wish has failed, and there's no point going on Thursday because the year is now the year you failed at that.

Chapter 10 gave Lally's finding that a single miss doesn't materially affect a habit that's forming. What turns the miss into the drop is your reading of the miss, and the reading is nearly always a verdict about yourself. Wohl, Pychyl and Bennett followed 134 first-year students across two exams and found that those who forgave themselves for procrastinating before the first exam procrastinated less before the second. That's a correlational study of students, so hold it loosely, but its direction is the one I'd expect. The verdict after a miss doesn't prevent the next miss. It makes the next one more likely, because the wish is now a sore place and you'll avoid pressing it, and the way to avoid pressing it is not to think about Thursday.

Here's what I think is going on, and it follows from chapter 8. The wish is all or nothing because the wish is a picture, and a picture is either intact or spoiled. A run that was missed spoils the picture of the person who runs every day. But a Tuesday sentence isn't a picture. It's a line on a week, and a week with two ticks and one gap is a week with two ticks in it. The Sunday five minutes, in chapter 19, looks at the two ticks and the gap and asks what the gap was made of. It doesn't have a place for a verdict because nothing in it is about who you are.

There's an honest objection here, which is that some slips are the start of the drop and pretending otherwise is how the drop happens. That's fair, and the answer is the Sunday. One miss is noise. Three in a row is information, and the information is almost always that the sentence is too big for the Tuesday it's meeting, not that you're the wrong sort of person. Chapter 22 is about what to do with three in a row. The short version is that you shrink the sentence. You don't retire the wish.