Chess Masters and Grandmasters practice dealing with different scenarios they might encounter. By practising the moves over and over, they develop habits and processes they can repeat effortlessly.

You can do the same thing with your emotions. Training your feelings and emotional responses can help you to form habits you can rely on under pressure. When you're under emotional stress, you'll avoid panicking, which will help you to make good decisions.

When you see someone make a big mistake, you may think, "Well, that's what they get." or "I've been there; it will help them toughen up." Those reactions are unhelpful. They don't do anything for the person who's suffering nor for your relationship with them.