Imagine you’ve had a bad night’s sleep. You’re running late in the morning, you have something difficult happening at work, and you’ve been worrying about money for several days.
On the way home, someone is rude to you in a store.
Normally, you might be irritated for a few minutes and forget about it. This time, you’re furious. You keep replaying the interaction after you get home. You snap at someone you care about, can’t concentrate on what you’re doing, and have trouble falling asleep that night.
It would be easy to focus on the incident in the store. Why did something so small affect you so much?
But the incident wasn’t the only thing you were responding to. It arrived after a bad night’s sleep, a rushed morning, a difficult day, and several days of worry. By the time it happened, there wasn’t much room left for anything else.
This is capacity.
At any given moment, there are limits to how much you can manage. Attention is limited. Energy is limited. So is your ability to tolerate frustration, uncertainty, noise, conflict, and emotional strain.
Those limits aren’t fixed. The same person can have plenty of room one day and very little the next.
And not everything using that capacity is obvious.
Monitoring other people’s reactions takes something out of you. So does holding yourself tense, rehearsing what might go wrong, worrying about something you can’t resolve, or carefully managing what you say so nobody becomes upset.
You can therefore be using a great deal of capacity even when you don’t appear to be doing very much.
As long as the total load remains within what you can carry, things continue to work reasonably well. You concentrate, manage your reactions, make decisions, and recover from ordinary difficulties.
But load accumulates. Eventually something can push you past what you can currently handle.
When that happens, the effects may appear in several places at once. You become more irritable. Concentration becomes difficult. Ordinary decisions feel complicated. Your body stays tense. You sleep badly. Things you normally tolerate suddenly become unbearable.
It can seem as though everything went wrong at once.
But the last thing that happened didn’t cause all of it. The rude person in the store didn’t create the exhaustion, the worry, the tension, and the poor sleep.
They were simply one more thing when there wasn’t much capacity left.
This is why functioning can change so dramatically from one day to another. The situation in front of you may be almost identical. What you are already carrying is not.
Sometimes what looks like an outsized reaction to one small thing is actually a response to everything that came before it.