In business, the situation is usually even worse. The customer needs some problem solved. They assume the easiest way there is to get a different problem solved. They ask a customer support-type person about that. The CS person assumes a solution is best, and then go to a project manager. The PM assumes a particular implementation is best, and goes to a developer.
By the time the developer is trying to solve the customer problem, it has been transformed into a different problem at least four times, by mere assumptions that rarely have anything to do with reality.
Always, always ask "Why am I doing this? What evidence do I have that suggests this specific thing absolutely needs to be done?"
One of my favourite quotes is "It ain't what you don't know that gets you in trouble, it's what you know for sure that just ain't so."
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It's not a small effect either. I've heard serious, well-reasoned estimates ranging between 50 % and 99 % of our work being completely unnecessary busywork.
Imagine that. In the most pessimistic (optimistic?) case you could spend half the year sipping drinks on a beach and still get just as much truly useful work done.