Why your reaction differ for the same situation based on the person you are dealing with?

Some people have strong personalities and dealing with them is like a game of chess or a battle that requires strategic thinking and planning.
Again, you might deal with overly sensitive and fragile people, and you will need to be hyper-sensitive so that your reactions are not considered hard-hearted or mean-spirited.
Overall you need to be a constant diplomat.

Hi - Same situation but different peosons, it happens, coz temperament and the personality of every individual is different, one who is not capable of what the other person is obviously behaviour will be changed, some people can easily handle the difficult situations, where as the some cant, they take time, so we have to choose the one who is easy going, tough, emotionally stable to handle the situations smartly...

because the person is a part of the situation

and every person has his own attitude so i can motivate you by other way than someone else and vise versa

because of the weak planning of the matter and in the talking time more matters will arise and due to the negotiation also it will be differ.