Be unselfish. That is the first and final commandment for those who would be useful and happy in their usefulness. If you think of yourself only, you cannot develop because you are choking the source of development, which is spiritual expansion through thought for others.
“Let the professors of Christianity recommend their religion by deeds of benevolence - by Christian meekness - by lives of temperance and holiness.”
“Sanity and clarity are more important for me and I'm willing to give up a lot of shimmer for it. I'm willing to have more boring friends, who are sane.”