Pathetic Moments in Marketing

We know we have great criminal minds. We believe we have writing talent. But who told us we had to understand marketing, selling through, contracts, and returns?
I thought it might be interesting to hear authors' stories concerning their WORST marketing/promotional/sales idea. Be brave: tell us all the sordid details.
Here's mine.
Early on, as I looked for ways to sell my historical novel, I read advice that said authors should look for non-traditional places to offer their books. "Don't just contact bookstores," the advice ran. "Look for places where people who like what you write congregate."
I looked. I pondered. And I discovered Renaissance fairs.
What a great idea! Hundreds, maybe thousands, of history lovers would walk by and see my book. Surrounded by all that pageantry and ambiance, how could they resist?
I contacted several fair organizers. Most ignored me completely. I was a little miffed. They could have a real historical writer on the grounds, and they passed on the offer? One, however, was quite excited to have me attend. The fair was in Florida, I'm in Michigan. All right, it's a road trip.
Then she asked what my costume looked like. My costume? "Oh, everyone has to be in costume," she said. Hmmm. Okay, a long skirt, a colorful blouse, and slippers. Instant costume. Of course my hair is chopped shorter than any Renaissance boy's, and I can't operate without glasses, but it will have to do.
What followed was a series of mini-disasters. My husband ended up unable to go with me, so I drove to Florida alone. The woman who booked my appearance broke her foot the day before I arrived and was so stressed I feared that a heart attack would follow. And of course, it rained all the first morning. Fair staff hurriedly moved my table into a nearby shelter where I was obscured by racks of T-shirts and souvenir swords.
Worst of all, I learned what might be obvious to others. People do not attend Renaissance fairs to buy books and then carry them around for the rest of the day. They prefer to walk around gnawing on huge turkey legs, buy cheaply made maiden wreaths, and watch hired actors strut, preen, and entertain. Most people walked by me without a glance. A few were kind enough to take a bookmark, one of which I later saw in the bathroom trash basket. One person in two days bought a book.
I learned from the experience, so it was not a total loss. Now I think before committing myself to an event. What a writer wants is sales (first choice) or exposure to readers (also good). She does not want to compete with jugglers, belly dancers, or anything else that is ten times more colorful than she is. Oh, and always bring along a garbage bag. When it rains, those pretty book covers can get ruined really quickly.
Now it's someone else's turn. What's your worst marketing/promotion/sales decision?