One of the toughest things for younger people and engineers to understand is how crazy complicated most businesses are these days. Growing up and going to school, everything is explained in a few sentences. Insurance is a bunch of people pooling their money to deal with risk. Logistics is the process of getting something or someone from point A to point B as quickly as possible.

So a couple smart young men thinks, "Let's make AirBnB for <industry>. At a high enough level of abstraction, it's just matching buyers and sellers." Then one of two things happen.

(A) They talk to a bunch of people in <industry> and realize that people have spent decades learning these industries and it's going to be a long slog to even understand what's going on in <industry>.

(B) They don't talk to anybody and build a simple marketplace in a few months and get very little traction. Then they either do (A) or go out of business.

A lot of good startup advice these days can be summed up as "talk to customers." Hopefully all that talking means you're actually learning something.