[eitally]

Agreed. Often the most challenging part of being a PM (besides coercing xfn collaborators to care about your priorities) is getting agreement on the amount of research that needs to have been done to justify a new feature, product or user journey. This is usually either business case development + ethnographic user research OR confronting of technical debt and engineering limitations/opportunities ... and it's rare to get everything right the first time. It's also rare to work in a place where a PM has the luxury of dedicating enough time & resource to create a complete requirement before the tech teams start working.

I also read "shot down" as a constructive and expected feedback mechanism. In small teams, it might be the TL or eng mgr who provide this feedback, but for larger product business cases are often required for review by executive stakeholders, and they will always be terse, hopefully constructive, but frequently come across as overly negative. Why? Because they're gatekeepers and it's their job to ensure the best opportunities are pursued and the rest are either back burnered or sent to the graveyard.