Years ago abroad, a few of us were swapping stories of bargaining and my friend David told me of an attempt to buy a rug in a rug shop in Cairo. He offered what he thought was a well-crafted low-ball offer, in hopes of moving to an acceptable place in the middle.
The owner looked startled, grabbed David by his shirt and rushed him to the door and shoved him into the dusty street. He slammed the door shut and flipped the sign to "closed".
We agreed that this was the most spectacular fail at negotiating we could recall.

