When you are offended at any man's fault,
turn to yourself and study your own failings.
Then you will forget your anger.
- Epictetus

All the world is full of suffering.
It is also full of overcoming.
- Helen Keller

Ninety-nine percent of the failures
come from people who have the habit of making excuses.
- George Washington Carver

Fall seven times, stand up eight.
- Japanese Proverb

It isn't the mountain ahead that wears you out;
it's the grain of sand in your shoe.
- Robert W. Service

Where there is no accusation of "fault,"
there can be no anger.
- Jonathan Lockwood Huie

Sometimes "bad" things just happen. Try to avoid lashing out at whoever is handiest - your spouse, your family, your friend, the government, God.

Further reading: How to Deal with Anger

Revenge is Never the Answer

When You Have Been Wronged