Mrs Steve always knows immediately when I have stolen chocoate from the large stash she keeps in a cupboard. The bars I take are always out of date, having been in there for a year or more. I don't remove any bar that isn't there in multiple quantities and I leave no crumbs and I hide the wrapper deep in the rubbish bin under the kind of detritus that you would not want to rummage in. No matter. She may not have visited the cupboard for weeks, but my transgression is always detected within a day. I put this down to a combination of telepathy, mind-reading, intuition, supernatural powers, quantum-induced magic and sheer viciousness.