Hard Work and Success
Work hard in school, you usually succeed. All the "problems" will come from the limited class material (lectures, books, notes, etc.). Simply mastering all this material gives you the knowledge to handle any and all possible problems on this path.
Jobs are another example of a place where hard work usually leads to success. There are pre-defined set of possible "problems" well documented and mapped out. If you work hard, you are likely to succeed and grow within your company.
In "real life", hard work does not guarantee success. You can work hard on the "wrong problems" and not succeed. There are no books which you can master and expect all problems to come from.
Therefore, the first task is finding a problem to work on. This task seems easy, but I believe it has the biggest impact on your life and future happiness. It is also possibly the hardest part of the "process".
This contrast becomes clear when looking at founders. Two founder friends, equally smart, and working equally hard. The same hours, same dedication, and same focus. One already has massive success and the other is stuck in place for years.
It is sad to see smart people not change directions when things aren't working out. In fact, the smarter, and more resilient they are, the more likely you are to persevere working on the wrong problems longer and harder all while getting nowhere.
Finding the right problem should be the first problem for smart and ambitious people. How to find problems is a topic for another day. Often, the same amount of effort is required to succeed regardless of the problem's nature. The returns, though, are massively different. This contrast in returns alone is incentive enough to find the right problems to work on.