At the above photo we see a Japanese policeman, why did he choose that profession? Did he have a choice? Maybe his father and grandfather worked as police officers and he was expected to follow in their footsteps, no questions asked. 
He might have dreamed of being a policeman since he was five years old without any family connections to the profession.
A third scenario is that is switched work mid life and did what he always wanted to do. The latter is, what I would say less typical. 
A fourth option is that he ended up at the police academy by coincident, more or less.
Many times we choose our professional path without thinking it through thoroughly. You begin to study towards something you don't understand the consequences of down the road. We are only aware of a part of the end result. Let me give you an example. You are very passionate about becoming a physician, a surgeon, helping people. This requires long study times, you have to sacrifice things to be able to keep up. It's about ten years of studies after high school. Then there are long working hours. This professional life choice isn't easy to combine with a happy family life. Especially, if your spouse has chosen a similar demanding career. It many times requires that the spouse has a less demanding work or stay at home in charge of family and children. That's the normal life of many surgeons. You can choose different paths when you are done with your studies and internship. The road less traveled requires thinking outside the box and many times it requires a good business sense what ever career you choose inside your chosen career. Think about that, many professions give you choices within the profession itself.
I don't trying to discourage you to choose a demanding career. The bottom line is; think it through, and then think it through, AGAIN! Be aware of all the cons and pros and then, make an informed decision.                                                        

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