Working hard entices you into a spiral in which your underlying mood dips, day by day, until one day you realize you’re only plodding on because of stubbornness. This descent seems barely noticeable. And then you’re there. Where you are isn’t pretty. At that point you need a circuit breaker: a word of encouragement from a friend, a bracing bike ride, or a bottle of wine.
In the space of one day, sometimes only an hour, perhaps even just over a single minute, you’re transformed. You run to your desk.