I was reminded of a quote this week: "You can be anything you want to be, but you can't be everything you want to be."
God damn that's true. Both halves of that statement act as a counter to incorrect assumptions which many people hold.
Firstly, lots of people don't believe that they can seriously change their life direction. Sure, they can get a new haircut or stop drinking so much or start a gym routine, but they can't start an entirely new career at 40 years old or leave a long term relationship they're unhappy in or move to another country.
Almost all of the world is at your feet and you can achieve far more success and change and happiness than you imagine. Any limiting beliefs you have about making change are held by everyone else too, so breaking through those beliefs immediately selects you out into an unbelievably small cohort with a massive competitive advantage over everyone else.
You can be anything you want to be.
Secondly, most people presume that their capacity for juggling multiple projects and life goals is way higher than it actually is. You have a limited amount of time on this planet, which means that even if you never slept, ate or got distracted, there are a finite amount of things you can do.
Many of these things are contradictory. You cannot find a new partner by going out 3 times a week whilst working toward a promotion whilst saving as much money as possible and getting in the best shape of your life.
You have to focus on progress toward a specific thing in the medium term or sacrifice meaningful progress toward everything in the long term. Gains disproportionately accrue to people who go narrow and deep on a small number of projects precisely because most people are going shallow and wide.
If you do one thing and someone else does two, even if your skill level is the same, you're making twice as much progress in the thing because you're spending double the time and effort on it. Learning to say no, choosing your highest points of contribution to the world and committing to them, and deciding in advance what you're going to suck at is crucial to making meaningful progress.
You can't be everything you want.