A seventh sustainable happiness activity is learning to forgive.

Forgiveness can break the downward spiral of revenge (and reward others with the same evil)

Forgiveness is not a single event but a process.

Forgiving you can do unilaterally (ie, even if the other person is not open to it).

First look honestly at your own share.

Then determine the part of the offender.

Make, if possible, a loud and clear protest ( "This should never have happened!").

Decide what you need to restore relations.

Communicate this to the perpetrator.

Release the other; set the other free; give (if you are a believer) it into the hands of God.