How about maximum viable product definitions for go to market? I've worked with PMs that have engineering build-build-and-rebuild delaying release until they feel it is "good enough", or what I think is really going on, "perfect". Then it gets into the hands of users who don't care about most of what the PM felt was important or necessary. In those cases (what I call "Steve Jobs syndrome) it would've been nice to say the product was limited to doing x, y, and z for the release.