Husband (having just arrived back from a trip to Russia): "Have you seen my keys? I left in a rush on Tuesday morning and didn't have time to look for them..."
Me (mentally rolling my eyes): "No, I haven't."
Husband: "Well, can you just check in your bag? You were the last one to use them..."
Me (sure of my ground - I always put my keys in exactly the same place as I come back into the flat and have never lost a set): "What are you talking about? I always know where MY keys are. Why would I use yours?"
Husband: "Well, you did this time. Can you check? Please?"
Me (huffily putting my hand into my bag): "I don't know why I'm bothering. I'm not the one who lost the spare car key. I'm not the one who loses any keys. I'm... (oh, shxt)... the one who has to own up when she finds your keys in the side pocket of her handbag..."
Humble pie, anyone?