As with programmers, it's often hard to tell the lazy from the great, because economy of motion runs with competence. Sometimes copy-and-paste gives you the wrong agreement for your deal, but it's cheap and easy for the lawyer. A different lawyer may glance dozens of alternative precedents in their mind's eye before choosing which form (or pieces of forms) to compose into an agreement for you.

When you dress for an occasion, you start by picking items out of your closet. If you don't have what you need, you may go to the store and buy off the rack. If the occasion or your needs are very special, you may have ready-made items tailored, or may even have something made for you. Good lawyers work similarly.