Gratitude is a duty which ought to be paid, but which none have a right to expect.

You owe thanks when someone helps you. You are not owed thanks when you help someone. Both halves matter, and the second is the harder one, because a kindness given with an invoice attached was never quite a kindness. Waiting to be appreciated turns generosity into debt collection, and it sours what you gave.

Pay what you owe first: think of someone whose help you never acknowledged and say so this week, late as it is. Then look at where you are quietly keeping score, and let that account go.