The following meditation is known as "The Divine Abodes" or "The Four Immeasurables". Reciting these words to ourselves is always appropriate, no matter what the circumstances. Start by saying "May I have happiness", etc., through all four lines; then repeat, inserting the name of someone you like; then again with the name of someone who's neutral to you; and
finally with the name of someone whom you don't like. (It may take a while before you are comfortable doing this for the ones you don't like - but it's very important in the long run.) This practice is beneficial for us and for everyone with whom we come in contact.
May all living beings have happiness and the causes of happiness.
May we all be free from suffering and the causes of suffering.
May we always rejoice in the happiness of others.
May we abide in equanimity, free from attachment and aversion.
And a wonderful affirmation from Raymon Grace:
"May I always be in the right place at the right time to do as much good as possible."