We just have to do it.
That thing you know you have to do, the one you promised or the one that is right. The one that takes extra time, but helps others.
You have to do it, and you have to stop waiting for the correct motivation to do it. That's the trap. The devil's in the motivations. He doesn't want you to do it.
Satan can't assail the good thing. It's good and he can't change its goodness nor its impact on who receives it.
So he sets out trying to keep you from doing it at all. Listen to the whispers today - "He only apologized because he HAD to," they whisper. "He's helping those people so he can get people to look at him."
Here's a good one: "I will do it, but I'm just not in a good place right now. I'm too (fat, tired, upset, insert MadLibs adjective here)."
When you listen to the whispers...who suffers? When you abstain from the good deed, the thing you promised, the obligation, the kindness, you suffer, and the recipient suffers. And people around them.
Worse yet, you're nowhere you're supposed to be. You were supposed to the thing, and let God do what he wanted with you and that deed. Screw the motivations. Do it.