The Lies of Secret Keepers

The phrase 'can you keep a secret' is abused from playground age until it turns into a ridiculous form of grandstanding. They are really asking if it is okay to use you as a sounding board to justify their choices or opinions. I'm sure we've all heard a 'secret' rumour or been confided in over a matter of questionable choice. Surely by confiding in another, the person in question is actually saying that they can't be trusted to keep their own silence.