The easiest way to stimulate regret about situations that haven’t worked out as per plan (as yet) is to ask counter factual questions like – “What if I’d done x instead of y?”
As such questions are a guaranteed way to drive us crazy, a simple principle that I’ve found helpful is – for every such counter factual question about a situation that didn’t work out, examine a situation that did.
So, if we want to ask ourselves – “What if I’d been better at keeping my mouth shut at that meeting?” or “What if I’d bought Bitcoin in 2014?” :-) – we also ought to analyze their positive equivalents. When was a time we spoke up and made a really positive contribution? When was a time we made a good investment decision?
Applying this principle does three things at once. First, we get to learn from situations which worked in addition to situations that didn’t work. Second, we begin to appreciate the many times things have worked out well.
And, finally, we come to accept the fact that we did the best we could with what we knew. Now that we’ve learnt from it and know better, we can do better.