OK, this didn't happen to me... but to an IP I was working with.
The IP was transitioning NG Huey pilot's to UH-60s. The student was a high time Huey pilot - but had never flown anything with wheels. The student had just completed a landing and commenced taxiing to the hangar apron area. Hangar was to the aircraft's left. SOP was to taxi, turn right, and stop so that the aircraft could be dragged backwards into the hangar.
The IP (left seat) told the student, "unlock the tail wheel" the student did not respond. The aircraft approached the apron, but due to the locked tail wheel was converging with the hangar door. The IP said again, "unlock the tail wheel." The student still did not respond. The hangar was getting closer and right pedal was going in, but the Hawk maintained its converging course. The IP finally shoved his face in front of the student (which then meant he wasn't looking at hangar) and said, "UNLOCK THE TAIL WHEEL GODDAMIT!" to which the student replied "Oh" reached down and punched the switch. By now there was sufficiient right pedal that when the wheel unlocked the tail swung violently to the left. The tail rotor became "involved" with the hangar door, the tail boom bent and the aircraft went up onto its left side. The main rotor disintegrated, sending high velocity bits and pieces through the hangar walls, the other aircraft in the hangar and the offices in the back. At that point the safest place was probably inside the helo. Amazingly no one was seriously hurt.
We always concentrate on the big things (engine failures, autos), but a little thing like a locking tail wheel can scew up the most experienced of stick jockeys. It's always the little things.