Juggle with emotions !

Man is very complicated biologically. His composition is still 100% not understood. Reasons why certain things happen in certain way in human body is still unresolved.
His emotional configuration on the other hand is much more complex. He is known for his unpredictable behavior. Again and again he proves that his actions and behavior can never be judged. Sometimes I wonder what Artificial Intelligence is trying to achieve. AI is my subject of interest and targets on making the computer as smart and as intelligent as human being. Humans themselves fail to predict how they might react to some situations. For this reason AI was redefined as making computers rational not human like as humans are not rational always.
Two good people unaware of each other came in contact because of me for some common goal. There was a verbal commitment made between these two on the common goal. But due to unpredictable situation one of the people broke the commitment. The action was very much valid when you look at it from his perspective. The situation which arouse was least expected and occurred after the commitment was made. I was informed about this and I expected the other person to take it calmly and understand the situation. I predicted a wrong behavior. The second person took this very critically and blamed me as well. After few days things have reassured. But I still wonder why my prediction went wrong. Where was the mistake? Was it my mistake that I was un related to the commitment hence I dint see the matter as a dent for the second person. Was it the mistake of the person who broke the commitment due to some situation? Was it his responsibly to keep up his words irrespective of the situation. Or was it the mistakes of the second person who dint try to think this kind of situation can occur occasionally.
Or is it just human tendency to complicate simple things?
There was some bitterness between two intimate friends. Both wanted to talk to each other from long time. But when they spoke one among the two looked clumsy which made the other person upset. Hence the two had a small clash. The fight was resolved in no time. But after a day passed, the clumsy person named the upset person’s behavior as an act. Some things are crystal clear. The excitement that was there in a person was broken down by the other and it was obvious for that person to be upset. How can this get tagged as an act.
A person is always immersed in negative thoughts like what if he loses the job very next day, every other person who interacts with him wants to cheat him, and every other person in his life fails to understand him. He lacks positive thinking attitude. When someone tries to tell him to turn positive he hates that person as well.
I wonder why humans are so complicated. Sometimes they fail to catch others emotions, sometimes they fail to respond back and sometimes they predict wrong behaviors. My future research has something to do with human psychology. Hoping to find some answers.