Some people hoard newspapers and trash. They just can’t decide what to throw out so they don’t throw out anything. Their house becomes a trash dump.
Others hoard hurtful memories. These endanger us of turning bitter, grudging, inward, suspicious or anti-social. Everyone needs a sewage system connected to the heart to flush out the wrongs suffered, else we lose the joy of each day.
This is why Jesus urges his followers to forgive. From the cross, in excruciating pain, Jesus forgave his crucifiers. It is the model for us.