The stranger you pass has already survived a morning you know nothing about.

Everyone you pass has already been through a whole morning. There were difficulties, small victories, a phone call, news received, and none of it is visible in the two seconds you have of them. What you see is the surface of a life that is as complicated as yours.

This is the cheapest available source of patience. When someone is abrupt, slow, or distracted, assume there is a morning behind it. You do not need to know what happened to give them a little room, and giving it costs you almost nothing while occasionally landing on someone for whom it matters a great deal.