Self Improvement is dependent on forgiving those who have done you wrong..
* that ex, who cheated on you.. they are sleeping at night while you are sad and down and depressed - forgive them - NOT for them but for YOU.. then and only then will you be able to move on - leaving the baggage behind.
* that coworker or boss who would rather back stab to get ahead then to be nice and admirable... forgive them also for otherwise you will always be under their control.