"There is but one thing of real value - to cultivate truth and justice, and to live without anger in the midst of lying and unjust men."

- Marcus Aurelius

The most important and valuable single phrase in this quote is "without anger". Living one's life without anger as far as possible will more livable and bearable. However, being calm in all kinds of social interaction will also put you in position of advantage compared to those of us who let anger take over.
Of course, this kind of thing is much more difficult to implement than to say. However, understanding the value of patience and forgiveness is the necessary start.

One must remember that feeling of passion is a quite different thing than anger. Passion is a positive feeling and anger is a negative one. Passion drives you forward, but anger stops you on your tracks.
When anger is allowed to run its course unhindered one may concentrate energy on foregone insults and wrongdoings of others, instead of concentrating on the good works you are about to do in the future. One could even say that anger is about the past and passion is about the future.

Marcus Aurelius was a Stoic. He believed that humans are happier and more content if they are able to control their strongest emotions. This does not, however, mean that a person should not have emotions at all. Stoics did just think that one should never give the upper hand to negative emotions. Of course, one can also well overdo this, as well as one can be carried completely away by emotions.
In fact, the worst crimes against humanity have been done by people acting on the purest of emotions or because of hatred and fear. On the other hand, quite similar crimes have been committed by people who have thought that are acting quite rationally.
They have just had higher ideological goals and they have acted on them without letting human emotions like pity or sympathy come between them and achieving their higher ideological goals.

Marcus Aurelius - Wikipedia

The Inquisitors of the Catholic Church or the Khmer Rouge did not normally hate their victims as individuals. They had an overpowering higher ideal that demanded them to act the way they did. Their belief in a higher goal made them believe that people who could stop them from achieving of their noble goals had no value as humans.
The big thing here is striking the right balance between emotions and rationality. The goal should be that a person should be able to retain a basic compassion for other humans, even if he is aiming for a higher good for all of humanity. This has proven to be an extremely difficult thing to achieve.

Humanistic core thinking offers a base on which one can build even higher goals for humanity quite safely. In the center of humanistic thinking are the core values of universal human dignity and equal value of all human beings. When one builds on these building blocs, one can never stray too far from accepting that other humans have inseparable human value, even if they happen to have wrong ideas.
In fact, the very central idea of this quote works for just this humanistic goal. It says that you should be able to live and work in a world where other people are in your mind doing things in wrong way. If you will not let the anger take over you, you can retain the ability for trying to change them or the wrong decisions they have made. You will very often lose that ability when you react with pure emotions and anger.

This quote is also a call for moderation and permissiveness. I would go as far as to suggest that these things are the core things that have made possible the rise of modern welfare states.
The ability to compromise and work with people that have different ideas of the world is an extremely central thing in success of democracy. On the other hand, history has clearly shown the overwhelmingly best way to spread wellbeing as widely as possible in a society is just democracy.

Marcus Aurelius has a very active fan-page in Facebook at http://www.facebook.com/aureliusphilosopher

(This piece was completely refurbished on 27th of July, 2012.)