A related sales concept is forcing people to say no, even if you don't get a reason for it. This is why some very effective sales folks will follow up essentially forever until they get a definitive answer. It looks like crazy behavior if your mental model is "I brushed him off twice, clearly that is a constructive no, why can't he take the hint", but the rep's mental model is "I close deals all the time after the 18th unanswered followup. If I haven't gotten a no yet, there is insufficient evidence to exclude the possibility that e.g. they're just busy."