Situation 1: Meeting room with harsh comments and heated up discussions, You are confident of your point and so is the other person, that is why he yells at you, shouts so as to prove his point correct. What a mild smile does at this point of time is dismiss his anger. Its nothing personal between you and him regarding the point of debate, however this smile is absolute personal and a gesture that i like yous level of dedication for the debate and lets take it in a sporting spirit.
Situation 2: You had a bad meeting, all the points of your discussion were rejected. Your client is exhausted, and will yell at you for the rubbish argument with no results. He wants to show his anger that he could not inside the meeting room. Give him a mild smile, and let him fall in believe that every thing will be taken care of. Let his emotions flow out without responding much in return. Sometimes to stay quite with a sweet smile is what act as an effective medicine for a bad ache meeting.
Situation 3: Its some big official holding a position of power, and all he needs is some bundle of notes before he will grant his permission for the case. Its illegal, but you don’t have any other way out. A smile even in this case will help you. Help for what?? For negotiating a better deal for the trade. Every human likes to be liked and smile is a great gesture that you like the person in front of you, despite his being so mean and hungry for money.
Situation 4: You are here to sign a deal, chances are low. Irrespective of the weak points in your proposals and merits of your competitors proposal, what comes handy is a fake confidence and a lovely smile. Contract is already gone to your competitor, or it is in the last stages of being honored to your opponent, Smile for your last chance. You never know, the party might just love your attitude for the fight, or in any case you would be in the good books for them always.
Whatever the situation may be, smiling at it will give them a massage that you are not afraid of the situation. Irrespective of the strength of your opinion, your attitude is what will shine and you never know what the selection criteria is, the Opinion or THE ATTITUDE.