Emotions plays a major role in our day to day activities. People were emotionally attached from the past that is why their present is very much affected especially if what happens from the past is somewhat disgusting, embarrassing or hurtful.
If you have an argument with your brother, mother, co-worker or even partner yesterday, when both of you meet again today... pretend that nothing happened, just pretend that is just another day, another ordinary day that has nothing to do with the past. Smile, forget about the altercation, forget about the raising of voices, argument, misunderstanding, verbal war, fist fight etc. Just forget about it, live your day like it is a normal day and expect good things to happen.
It is easy, you will experience tension at first but if you are willing to face the awkwardness of the moment then you will be fine. When you talk to him or her, just be natural, never get emotional nor defensive. Always be in the moment and never show them that you are trying to escape or wanted to go to other place.
Because if you continue to give value to your ego then your business with that person will be affected too. Your day will be ruined, you will not get what you want, you will never operate normally.
Never take anything personally. Sometimes unfortunate things happened and nobody wants to hurt anybody. Sometimes argument takes place because of the heat of the moment, and that is very normal. Even if you are so kind, there will be times where you will still argue with someone, you cannot escape it even if you are a buddah or some kind of a meditation guru.
Just pretend that nothing happened and everything will be fine. Move normally, don't show any disturbance. Always feel confident, stay in control and never try to hide from somebody.
If you want to get things done, if you want to live a normal life again unlike yesterday.. always pretend that nothing happened. Detached your emotional connection from the past or from anyone. It is like starting fresh again, being excited again to embrace a new chapter of your life.
Forgive if you can but if you can't never plant any bad blood to anyone. Wanting to have revenge will just make you miserable in the end. You are the one who will get burned.