I avoid thinking negative thoughts during the day

Negative thinking keeps office hours. For a lot of people it is the twenty minutes after lunch when the blood has gone elsewhere, or four in the afternoon, or the particular stretch of the commute where the train goes quiet and there is nothing to look at.

The same thought at ten in the morning, with coffee and something to do, barely gets a hearing. At four it is devastating, and it feels like insight.

Track your own hours for a week and the regularity will slightly embarrass you. Then you know something useful. Not that the thought is wrong, but that four o'clock is not the time to decide anything.