From things I read and words people say, society seems to think forgiving is a weakness.
I completely disagree.
A forgiving heart is stronger than holding all of that anger and hurt inside. It only weakens a person to keep it. Being unable to forgive shows a lack of true understanding of the complexities of human nature. It shows a lack of higher mental and emotional capabilities.
Instead of holding on to whatever bothers you, instead of letting that bring you down, just set it free. Find other things to work on, instead of stewing over things in the past.