Buddha's doctrine: Man suffers because of his craving to possess and keep forever things which are essentially impermanent...this frustration of the desire to possess is the immediate cause of suffering.
It is true to say that the first kill can influence the whole future career of a fighter pilot. Many to whom the first victory over the opponent has been long denied either by unfortunate circumstances or by bad luck can suffer from frustration or develop complexes they may never rid themselves of again.
Nowadays, we are confronted by a huge gap between rich and poor. This is not only morally wrong, but practically a mistake. It leads to the rich living in anxiety and the poor living in frustration, which has the potential to lead to more violence. We have to work to reduce this gap. It's truly unfair that some people should have so much while others go hungry.
The 20th Century was a bloodbath, and for all the frustrations and failures of the project to unify Europe, the last five decades have been periods of unprecedented peace, growth, and prosperity in Europe.
There is no formula for generating the authentic warmth of love. It cannot be copied. You cannot talk yourself into it or rouse it by straining at the emotions or by dedicating yourself solemnly to the service of mankind. Everyone has love, but it can only come out when he is convinced of the impossibility and the frustration of trying to love himself. This conviction will not come through condemnations, through hating oneself, through calling self love bad names in the universe. It comes only in the awareness that one has no self to love.