You did something to someone — pressured them, mocked them, left them out, went along with hurting them. You know an apology is owed. You've known for a while. But every day you don't do it, it gets a little more awkward, a little more buried, a little easier to tell yourself they've probably forgotten, or it wasn't that big a deal, or it'd be weird to bring up now. The apology sits there, undone. Part of you wants to clear it. Part of you would rather just let it fade. But it doesn't quite fade — it just goes quiet, and waits, and surfaces every time you see the person.