Serious Question: Why do human beings have a tendency for self-destruction?

If you think about it, humans are always finding new ways to destroy themselves. Wars and discrimination are obvious examples. But have you realized that we always become too overconfident about ourselves no matter what ???? It is like we tend to take for granted that everything will be okay thanks to our potential, but is it??? This of course is somehow common in our society and it seems that we still p this kind of mentality to future generations without realizing it. It also seems that this kind of message gets recorded somehow in our subconsciousness and even though we know that it isn't okay to over speculate we still do it. The recession we are now experiencing is also another example of this situation. NOW, do you think that this mentality is exclusive to our race, society, and planet? Or do you think the other civilizations (there certainly have to be other civilizations in this vast universe besides us) that live in our universe could also share this mentality of self-destruction?? FINALLY, how do you think we can overcome this issue for our race's sake???? And please don't say things like "we have to remind ourselves of the consequences of our actions" or "we have to change" because those things just don't work. It just seems that we have to train our minds in an effective way to overcome this issue in order to ure our prosperity and future and , of course, to avoid "stupid" mistakes. What do you think???