Why is entrepreneurship often difficult?

Answer 1

Short answer:

Because its not a "science" there is no right methodology for finding what works and dynamically applying it to the problems you'll encounter.

bottom line:

There is no book or knowledge that contains the specific solution to the problems you'll encounter. But at the same, obviously do research but know that full answers are not available for your problem.

Steve Jobs quote

find what you love so you can find it easier to endure in the darkest hour where most people give up (recovering from failure (which is inevitable) is really important if you want to succeed )