Receiving a bill, or rather a statement, which tells you there is nothing to pay on your account.
Alan Bennett, writing about some of his favourite paintings, quotes E. M. Forster: "Only what is seen sideways sinks deep".
For a long time I knew of a restaurant called A La Bonne Franquette. It was only the other day that I realized that the phrase meant "simple and without fuss", which is how food should be prepared. That was the belief of Escoffier, who famously advised, faites simple!