We are greedy and selfish by nature. However, we are gifted with a brain that controls our behavior and emotions. If we use our brain correctly, then we are able to control ourselves of internal needs and external ones. We can control how much we want to consume and how much to give out. We control our will. We strive for moderation to keep the balance and avoid hurting ourselves (and others) because of our greedy nature.
That’s why everybody advises the other to do everything in moderation. It is easier said than done, but possible if we have that will and determination! In life, there is a limit that we can’t go beyond because then we will be destroying ourselves.