Keep your word. If you give your word (your promise), then keep your word...
OR admit with full-frontal responsibility that you did not keep it.
It's as close as anyone can come to a clean getaway.
My pissed-off-as-a-wet-cat syndrome comes calling again and again when I run into or hear about some dipwad who, as a means of thinking well of him- or her-self, promises to do something and then neither does it nor admits to having failed to do it.
You'd think I might get over this.
It's still like fingernails on a blackboard.
No doubt I too have failed ....
I DON'T CARE: it still pisses me off.