*Serious* question: do you believe that humans have free choice?
My thoughts. Yes, but to a limited degree. We have physical and psychological/cultural limitations. I can't decide to break a world record in running if I am a lousy runner. I might "will" myself into breaking a record, if I am a reasonably good runner.
The often repeated "positive thinking" affirmation "you can be anything you want to be, if you only want it enough and try hard enough" is a cruel hoax. It isn't so and saying this is likely to be damaging, adding guilt to disappointment. "I didnt get to be {fill in} because I didn't really try hard enough."
To illustrate that latter point, I said to a friend who was born in Poland "you can be president, if only you try hard enough." As expected, he replied that, having been born abroad, he is not eligible. I countered that if only he wanted to be president badly enough, surely he could get the constitution amended to allow it.
Absurd. Possible, but highly unlikely.
On the other hand, a positive attitude - optimism - and a "can do" enthusiasm will help enormously to bring results. There is something to "the power of positive thought."
There are psychological limits. You can do what you will, but you can't will what you will.