Someone accepted your apology when they could have held it over you. That was a gift, not an obligation.

Forgiveness is optional in a way that is easy to forget. Somebody who accepts an apology gives up a real advantage, because the alternative is keeping the thing in reserve and spending it later. Letting it go instead means they chose you over the leverage. That is a gift, and gifts are not owed, which is what makes them worth noticing.

Remember a time that happened to you, and keep it in mind the next time you are the one who was wronged. Holding something over a person is always available. Putting it down is the harder and better move.