Existential and deep questions might be very tough to answer as there is much abstraction and too many different options and answers.
Since we have limited capacity to process all the information, instead of asking:
What should I do with my life? ... Which has so many options that will overwhelm
We can use inversion to find a clearer path to answer a tough question:
What I should NOT do with my life... which is more specific and has a narrower set of options.
This framework is easier to solve. We have a better picture of all the things we don't like doing, or the type of people we don't like to be working with , etc...