It was the perfect photo op: In Nessebar, one of the oldest towns on Bulgaria's Black Sea coast, a wizened bagpiper played in front of a stone wall whose foundations date back to the 4th century B.C. The goatskin bag of his gaida was tucked firmly beneath one arm, and the loose white sleeves of his traditional outfit glowed in the summer sun.
After dropping a handful of coins in the cardboard box designated for tips, I caught the man's eye and motioned to my camera, asking permission to take a photo. He slowly shook his head from side to side while still playing. I stepped back and lowered my camera in disappointment. The piper gave me a quizzical look, and a few locals chuckled.
Then I remembered. Head gestures in Bulgaria are the reverse of ours, with a shake meaning yes and a nod meaning no. More precisely, their yes tends to be a subtle swivel to the left and right. If you're speaking to a Bulgarian who agrees with what you're saying, the gesture becomes more like a repeated jerk to one side, as if the listener is trying to chase away a pesky mosquito. Even Bulgarians can't explain the origin of these mannerisms. I smiled, shook my head, and snapped the photo.