Picking problems to solve is a function of attention. Wherever and whatever you’re paying attention to is going to reveal problems in that domain to you. Solving such revealed problems is going to absorb you and will reveal even more problems worth solving in that domain.
So this creates kind of a feedback loop.
Because every domain of life has such richness, it’s easy to get lost in this feedback loop and spend an entire life solving problem after problem in that domain. In fact, this is what (traditionally) is meant by a career. There’s nothing wrong with going deeper into a niche if one is mindful and conscious of it. However, in my experience, few people consciously choose what problems to solve because very few consciously choose what to pay attention to. ...