Mark Cuban says being told to focus on your passion is one of the biggest lies people are given regarding career advice. This is focusing on the wrong thing and does not account for the full picture. If you focus on only your passion you may not be considering what you are good at. He gives the example of how baseball was his passion, but pursing it would have been foolhardy considering he did not have the right skills. And no amount of passion would compensate for not having a 90+ MPH fastball. For me, my passion was football, but I similarly did not have the skills needed.
Instead, he says you should pay attention to where you find yourself spending time. In his words: "The things I ended up being really good at were the things I found myself putting effort into. A lot of people talk about passion, but that's really not what you need to focus on. You really need to evaluate and say, 'Okay, where am I putting in my time?' because when you look at where you put in your time, where you put in your effort, that tends to be the things that you are good at. And if you put in enough time, you tend to get really good at it," It is the areas you are good at that he suggests you double down your effort.
In my book, Trajectory: 7 Career Strategies, I discuss a similar concept and how the best scenario is when your interests and skills align. When this occurs you reach peak performance. All things considered, though, you must have skills in an area to be successful; passion without ability will typically result in futility and frustration, The best scenario, of course, is when you can align both. True sustained performance involves a level of both skill and motivation. It is worthwhile to note that people tend to like something more when they are doing well. Thus, you can build confidence and even passion for something by doing extremely well.