Long-term work teaches you how little one bad week actually means.

One bad week feels enormous at the time and disappears entirely at any distance. Long work teaches this directly, because you can look back at weeks that felt like disasters and find that they left no mark at all on the trajectory.

When a week goes badly, remember that you have had them before and cannot now recall most of them. That is not a dismissal of how it feels. It is accurate information about how much it will end up mattering.