Personally I would prefer "I told you so" from anyone I care about instead of these lamentations. Chances are high that I would completely ignore such input dep

Personally I would prefer "I told you so" from anyone I care about instead of these lamentations. Chances are high that I would completely ignore such input depending on the situation if I were the receiver. If I did indeed do a mistake, which doesn't have to be the case in business, it will be easier to learn from it if people communicate directly. If I am your supervisor chances are that I would package it more friendly, but it depends. More importantly is that we put this conflict behind us. Depending on the relationship it could be "I told you so, next time let us do X".