The cheapest mistakes are the ones you watch someone else make. Pay attention.

Experience is expensive when you buy it yourself and free when you watch somebody else pay. Most people watch anyway and take nothing from it, partly because looking closely feels like judging, so the lesson goes by unrecorded. The watching is not the skill. Turning it into something you would do differently is.

Think of one thing you saw go wrong recently, at practice or at work or in a friendship. Write a single sentence about what it cost and what you would do instead. One sentence is enough to make it yours.