A lot of theories in psychology are painfully equivocated. Because its a science, it tends to get approached by some like it was all numbers. The result is a theory that started at some spark of truth but overextended to the point where that truth became forgotten and replaced with a thick pile of analysis that isnt really saying anything. What I got here is a pretty simple theory The premise is that humans possess a need to control reality. This is an evolutionary measure: one has to be controlling about certain things or else he will lose control over his life and be unable to keep himself alive. By this fact, we can deduce that all humans are controlling by nature since this tendency is critical to survival. Here I define control as the desire to get what you want and the way one would go about doing that. This desire to get what you want is often challenged by reality. Naturally, you cant get everything you want. I propose that there are three different reactions that occur when this happens. One response is aggression. In response to not being able to get what one wants one tries to ,in essence, fight back. To them reality is acting as a defiant force; "how dare it disagree with what I want." They 'fight back' by attacking reality in some way. One way could be to attack passive aggresively by saying a sarcastrc joke, another by actually physically attacking something. Regardless of the multitude of ways it can be done what remains constant is the attacking of reality in through some means as a way to get back at it for defying you. I think that this also occurs not just when people are acting angry but also can happen whenever a person is confronted with a challenge of some sort. For example, Michael Jordan endlessly shooting jumpshots as a kid because he was unhappy with how good he was and wished to improve himself. Had he been content with himself (content with reality as it then was) he would have never bothered to continuously practice and improve himself; he would have never overcame the reality of being just an average player and not the greatest player of all time. Thus he must have reacted aggressively to the notion that he was just an average player. He must have cut away at that very notion with every time he played a game, with every time he would practice, with every jumpshot he would take. In their own unique way, all attacks on reality. Eventually reality would bend to his will and Michael Jordan would finally win in his battle with reality, going on to become the greatest player to ever live just as he sought out to do. Thus reacting with aggression when challenged by reality is not always purely bad thing. It can be said that the greatest inventions and acheivments of man started from this very source. From men who were very discontent with reality and very determined to change it into what they wanted. Another type of response to not getting what you want is giving up. You submit your defeat to reality and simply let it beat you. When youre resolved from this you feel a sense sadness. Its because you still want that which you originally wished to have but because you arent reacting aggresively, you are forced to live with this emptiness. Reality towers over you like a giant bully, pushing you to the ground. You lay there helpless as its booming laughter pummels you in waves. I think this particular response is the cause of depression in that you exist in a state where you perpetually want something but perpetually can never have it; trapping you. The third response to not getting what you want is acceptance. Simply put, you accept that reality will not allow you to have that which you want and you stop wanting it anymore: you move on. Of these three reponses two of them share, at their base, the same fundamental quality. Agression and defeat are both forms of resistence against reality with acceptance being an agreement with what reality demands.