Not just complaining
In your opening paragraphs you mention negativity and being able to find the hole in every plan. That is the problem I encounter much more that flat complaining without solutions. The 'Negative Nancy' or 'Downer Dan' is more often hindering a project rather that helping. I suggest: Assess whether the hole found was just for the sake of finding it or for the improvement / success of the project. Also, if you are smart enough to find a hole then you should be smart enought to help close it, just like complaining: have a solution in mind when presenting a complaint.