if we think only of ourselves, forget about other people, then our minds occupy a very small area. inside that small area, even our smallest problems appear very big. but, the moment you develop a sense of concern for others, you realize that just like ourselves, they also want happiness; they also want satisfaction. when you have a sense of concern, your mind automatically widens. at this point, your problems, even big problems, won't seem as significant. the result? big increase in peace of mind. so, if you think only of yourself, only your own happiness, the result is actually less happiness. you get more anxiety, more fear.