An annoying behaviour that wastes time and effort are comments that shift the goalpost after receiving an answer. Sometimes the cause is an incomplete explanation of their needs and some other times the OP is just requesting new "features" that may render inappropriate a particular strategy already developed in the answer.
What should we do to avoid shifting sands comments?
How do we deal with them without appearing as attacking the OP?
It's frustrating to contribute effort to a specific question to then see contradictory details or new requests not previously mentioned in the question.
I wonder if new users could be confronted with a checklist while editing their questions, designed to prevent this and other poor questions. Is that technically feasible?
Current tips seems insufficient