“You shouldn’t give circumstances the power to rouse anger, for they don’t care at all.”
Marcus Aurelius, Meditations.

Emotions exist to prompt us to take action to safeguard our needs and wants. We can be moved to avoid a situation in which we might lose the things we need, by either running away from it or dominating the perceived threat. Or we can be driven to seek out, seize and secure more of the good thing that we need. Emotions play an important role socially, signalling your need and intent to others.

But what if the other ‘actors’ in the situation are incapable of receiving or recognising your emotional signals? You need to be at work on time, but the train is late: does the train notice your annoyance? You’re looking for somewhere to park, but there are no places: does the carpark take pity on your predicament? Is it worth crying over spilled milk? The milk doesn’t care.