[zachsnow]

> is this not evidence of incomplete requirements?

Yes! But there will never be a complete set of requirements — indeed if you think the requirements are complete, you spent too much time on them and you aren’t looking at the problem carefully enough.

There’s a balance between calling for more complete requirements and being able to work with less complete requirements. The more you can correctly choose to do the latter, the more you “hone this skill”, the more effective you can often be.

(As a bonus, when you do call for more complete requirements, in my experience people will be more open to doing that work. They know you wouldn’t ask if you didn’t “really need it”.)