I've just been reading a blog post likening the examination of conscience to a dental check-up. Richard Verstegan has it that an unconfessed sin is like a pike in a pond, eating up the minor virtues like so many little fish. My own analogies tend to gardening (pulling up weeds, and such-like).
This afternoon I went at the brambles that had grown in under our geraniums, putting down roots every so often, and not sticking their heads out above the leafy cover. Weeds that put down roots without showing themselves, and thrive ignored, and are a bugger to get out (see picture), while more flamboyant weeds are pulled up quickly. Hm. Probably some sort of analogy somebody could make out of that. I'm too tired.