My DOH! Moment

I had one of those moments today! A little over a year ago I got a new cell phone. A Razr (pink, of course). Until today I didn't know how to turn it to speaker phone. Bob called while I was in the grocery store, and I accidentally hit a button that put his call on speaker phone. I could not figure out how to turn it off. I thought when I disconnected the call it would, but no. I fiddled with it for a little bit, but ended up abandoning my cart to go outside to call him back. It was a short phone call and luckily no one took my cart thinking they had to put it away! I had to pull out my book to figure it out, but now that I know how it works I might actually use it! :)

When was your last DOH! moment?