One of the biggest mistakes in the conduct of negotiations is to proceed on the basis of arguments which are conclusive and motivating from your own perspective. This works out splendidly. Provided that your negotiation counterpart ticks just as you do – which hardly ever is the case. This is the reason why your argument, despite its initial completely logical appearance, does not appeal to your counterpart.
The genuine art of negotiation consists in arguing within your counterpart’s world of thought.