When we confuse our language, and use words inappropriately, we begin to interfere with our own success. In the case of the word want, this can have horribly a damaging effect.
If my friend had truly wanted to learn to play piano, nothing would have stopped him from his daily practice, or from nagging me for lessons and help. I would not have to remind him to practice or that he needed to schedule lesson time with me; I would have had to teach him to shut him up.
And when we look at this on a broader scale, this use of the word want to mean something other that what it does, means that we go through life unfulfilled. It means that we have this wishlist of unsought dreams, never tried. And that way lies vast unhappiness. We think we want something, and we don't get it, and that makes us discontent. What most people mean by want is a wistful "wouldn't it be nice if . . ." feeling, rather than a true desire to do something.
The other meaning of the word want makes this abundantly clear. To want something also means to lack or to need something, as in "He died for want of food." That doesn't mean he died because he would like to have food, but he died because he lacked food. Want, in its other sense, is the need to fill that lack.