What I’m about to say may seem obvious, but this is a challenge that humans have been thinking and writing about for centuries. In that spirit, I’m going to let the Stoic philosopher Epictetus say it more eloquently than I ever could.
“The chief task in life is simply this: to identify and separate matters so that I can say clearly to myself which are externals not under my control, and which have to do with the choices I actually control. Where then do I look for good and evil? Not to uncontrollable externals, but within myself to the choices that are my own . . .” — Epictetus
If you have the ability to act, to steer a situation in a particular direction that is more to your liking, then, by all means think about your best next step.
But when events are entirely out of our control, when no amount of thinking can or will change the reality of your situation, where is the value in tormenting yourself with unhelpful thoughts? You are going to miss an important meeting because a storm caused your flight to be grounded. What benefit do you gain from telling yourself stories, (and they are just stories) ruminating about what others may think about the opportunity that may have been missed? This pattern, this layering of emotions on top of each other, getting frustrated by your anger at missing the flight, then ashamed of your frustration, then sad about your shame. Do this for even a moment, and what you’re now experiencing will bear little resemblance to the pang of emotion you felt when you first became aware of your predicament. How is that serving you?
I find a simple question helpful when I find myself in this kind of thinking spiral. “Is this under my control?” If after a little though the answer is an honest ’no’, I find letting go of negative thoughts becomes that much easier and can move my attention to things I can impact.