Sometimes things don't work out.
You can put in weeks, months, and even years into trying to achieve something and in the end it just won't happen. For whatever reason, you don't feel a sense of completion or satisfaction over the fact that you're doing the thing that you've put so much effort into. When you don't feel good about all that effort, you start to try and figure out what to do next. Maybe even look into becoming something or someone else because you hope that this new thing will give you that sense of satisfaction and good feelings you were looking for in the first attempt. Even though there's just as little guarantee that the new thing will do anything more for you. The only thing you can hope for is that it will be better than what you had before.
Of course, doing this can have its downsides as well. Mainly because you spent so much time and energy into it that people expected one thing out of you. Instead you gave them something different or the potential for something different. This can leave people confused and uncertain about how to deal with you. Not to mention, you aren't as young as you used to be when you put in the original effort. You're much older and can't do the things you used to be able to do. This means you're going to need to put in just as much effort if not even more to get to the same level that you did in your first attempt. You end up putting a lot strain on yourself and the people around you. They might worry you won't be able to measure up. When you choose something dangerous, they can worry something bad might happen.
The people in your new effort may also be younger and able to do more than you. It could be their very first effort. As a result, they might resent you trying to come in and doing what they have dedicated their lives to in their first attempt. Finding your way through these types of dynamics doesn't always work out well. Other people are going to be angry and frustrated with you for wanting to reinvent yourself. Unfortunately, there isn't anything you can do about that except try to win them over by being even better than they expect you to be.
The Rookie is fundamentally about trying to reinvent yourself. John Nolan, as played brilliantly by Nathan Fillion, has decided he needs to reinvent himself at the age of 40. Despite having built a life as a contractor and repair man, he felt it wasn't enough for him as a career. So instead he decided to become a police officer. Something that is obviously much more dangerous than his previous job. At the same time, there's a rewarding aspect to his new profession. The desire to actually help people and to stop problems before they get too dangerous for other people. It gives him a sense of satisfaction and purpose that he never felt before.
It's a fascinating process and you should take the time to explore reinventing yourself by checking out The Rookie as soon as you can.
The Rookie is available on Hulu as well as Disney Plus and CTV in Canada.