In a funny way, the way you live each day is practice for the way you will continue to live. You’re actually rehearsing your ways as you go along, and everything you do prepares you for how you will naturally react in a situation. It’s quite like in the movie Karate Kid, where the kid is made to practise menial tasks that seem pointless but are actually designed to teach his muscles how to move so that he doesn’t need to think about it. He’s building muscle memory (as well as the strength in those muscles) so that when he needs to react quickly, he reacts effectively.

We train our emotional reactions in the same way. Each move in a particular direction strengthens our muscles that way. But we mostly don’t think about the reaction we want to have, and how we can do something about it, so we end up training the wrong muscles, and laying down the wrong reflexes.

Of course all this means that when you do try to make a habit change, you’re fighting against the weight of years of travelling naturally in a different direction. It’s not going to seem normal. This will make you feel uncomfortable and you will feel wrong. This will make you want to give up. But it will to take some time to make it your new normal. Like an old comfortable pair of shoes – when they’re finally too worn out to wear without being embarrassed, and you have to get a new pair, they feel all wrong. It’s so much easier to put on the old shoes, which feel like part of you. That’s because you put the time in to make them that way.

If you don’t want anger and bitterness to be what defines your life when you’re old, you need to start putting them aside now, in small ways. You can’t live one way now and expect to be someone else when you’re older. You rehearse who you want to become – or, for most of us, we usually rehearse who it’s easiest to become.

What you practise literally becomes your practice. (This sentence works better in UK English.) There’s a theory that it takes 10000 hours to master a skill. Many of us have put that time into a cutting sarcastic wit, the ability to manipulate others, or the dubious talent of being able to find something to be miserable about in every situation. We’re undoubtedly masters, but it’s not serving us well.

Turning this around is hard work, and it’s easier not to. But it’s your life – how do you want to live it? Then practise.