Absolutely, undeniably true. Which is why God wants us to forgive and let Him deal with those who have wronged us ... He's just trying to mitigate the harm we will do to ourselves by bottling it up. And, He also knows that I am an equal-opportunity-offender on the other side of the coin who is in desperate need of forgiveness, often times, too. It's a very sharp, two-edged sword we foolishly try to handle and invariably end up harming ourselves, coming and going. Good thing He's there to save us from ourselves, eh?
The essential American soul is hard, isolate, stoic, and a killer. It has never yet melted. ~ D.H. Lawrence