My Phone, Usually.
One day I was in a somewhat hysterical panic thinking I'd lost my phone, as I'm prone to misplacing things. I searched the whole upper level of the house to try and find it because I just -knew- that was where I had it last. I had just begun to complain to my family when Spiderbait's "Black Betty" came blaring from the front of my shirt, startling me. Hysterical laughter ensues.
Perhaps "I often forget things in my bra" is more appropriate.