Resentment is a quiet consistent dissatisfaction directed to some situation or people. It’s a hum of unhappiness.
It builds through a sequence of your choices, and you, the one holding resentment turns the person who places it inside you, into a victim of this feeling. A misplaced sharp remark made under your breath replaces those times you held your tongue. Rolled eyes reminding you that you decided to stay when you should have left. Understanding turns into sacrifice.
Resentment slowly creeps in, unseen. Like rot in the foundations of a house, you can repaint the walls and change the furniture but the house will still come down.
I am resentful, but I am also sad that I was not brave enough.