A few months ago I couldn't find my purse/backpack hybrid thing. This was a problem, because I had cash, my bank card, my bus pass and my ID in there. I looked for it all over the house for two days, and became convinced I'd left it somewhere when I was out and I'd never get my stuff back.
I finally found it...underneath my mattress. I had taken the mattress off and laid it on the floor a couple days before, so that my dog could lay beside me on it for a while. (She's getting older and experiencing some stiffness in her joints, so she has a hard time jumping up like she used to). Apparently I had put my purse on the box-spring at some point, then replaced my mattress on top of it without noticing it. Then I had slept on it for two nights without feeling a thing.
I'd be a terrible princess in "The Princess and the Pea".