When I started exploring entrepreneurship in college, I was exposed to the education paradigm - write a business plan. I was a good student. I wrote 9 business plans in 9 months for my first startup. It turns out, that was not the best way to spend my time. Yes, planning is essential. But it needs to be done in the right proportions. Less at the start. More as you mature.
Professor Carl Schramm recently wrote a carefully researched book called 'Burn the Business Plan.', listen / read to an interview about the book's highlights here.
Hat tip to Jim Geissman.