I have reserved myself in learning how to deal with people & situations where, a simple heads up, would have avoided lots of wasted effort.
You have to go into every situation, asking questions, because odds are...Someone has already addressed it or knows something about it. If you don't bother & start looking into how to solve the particular problem without wondering if someone else knows something about it...You will eventually say to yourself...Well, that is a few hours I'll never get back.
The reasons people don't bother to adequately communicate? They are varied from simple apathy, to vindictive hostility. It's also hard to have intelligent dialog with the radically stupid by the way.