Patience is cheap when you are rested. Standing in a pharmacy queue on a Wednesday, on an hour of sleep, with something unresolved at work and the person ahead taking a very long time over a loyalty card, it costs everything you have.
What gets called impatience is usually depletion wearing a rude face. The supply is not a character trait. It is a resource, and resources go down.
Which makes the days you manage to be decent on nothing the ones that actually count for something — and those are, without exception, the days nobody notices.