Sometimes you need to let go of things that might represent potential monetary gains, if only for the peace of mind that only comes from being the one to let go.

“It's only after we've lost everything that we're free to do anything.” ― Chuck Palahniuk, Fight Club

“You are not your job, you're not how much money you have in the bank. You are not the car you drive. You're not the contents of your wallet. You are not your fucking khakis. You are all singing, all dancing crap of the world.” ― Chuck Palahniuk, Fight Club

Present value of peace of mind is worth more than potential future value of most things.

And grudges are not worth the cost.