A clock ticks the same all day. You only hear it at night when everything else goes quiet. Same with your conscience.

Noise is a good hiding place. The thing you did or failed to do has been there since Tuesday making the same small sound, and you only hear it at one in the morning when the room is empty and nothing else competes. Quiet does not create guilt, it just removes the cover. That is why people keep their headphones in.

If something keeps surfacing at night, handle it in daylight when you have more to work with: say sorry, hand the work in, tell the truth, pay the person back. Most of those are twenty minutes of discomfort, and the ticking usually stops once you act.