In the 1950's a man was travelling around Africa, interviewing leaders about life under colonial rule. On one of his journeys, he was going to meet an official when the train he was on stopped. News got through that a train further down the line had derailed and a long delay was expected.
It was hot and people got off the train as they waited. The man was upset at the time it was taking and how it was making him late. He observed the African people around him were happy as they talked. He decided to ask why they were happy when their journey was disrupted for so long. In reply it was explained that they were happy because they were not on the train that had derailed. A six hour wait was much better than possible injury, or even death.
So here was a traveller annoyed about the time they had to wait and the locals were glad to be well and unhurt. Life throws up unexpected events, and plans are affected. However, there are always more than one way to look at the situation. Either we can see how we have been affected negatively, or appreciate that it could have been a lot worse. Besides, getting frustrated at something we have no control over is pointless, even unhealthy.
The man learned a lesson. The local people maintained their joy while they waited. He had lost his over something he could do nothing about. We could always see how circumstances could have been better, and get wound up. Instead, we could reflect on the bigger picture. Accepting that things go wrong and finding an upside to what happened will lighten our mood. In that negative moment, we might even discover there is something to be joyful about.