Let's see. Was it in Ireland when a storm broke the moorings on a pirate ship we created, trashed the dock of our lakeside set, and almost killed two film crew members before sinking? The time a pissed-off pro football player threatened (really) to kill my partner for not putting the player's sister-in-law in the spot? Nah. I think it was the time a director, upset with the client's obsession with the food styling on a plate of nachos, went off the edge. To paraphrase Eric Stratton from Animal House: "You didn't throw that plate of nachos in front of the client, you threw that plate of nachos on the client."
I hired a Danish production company to hire a Spanish director and get a crew from Prague to shoot in Prague. A scheduled two-day shoot took five. It was the language (barriers), the cultural things, the approach to the way they do the work, and the rich and varied temperaments. It was highly entertaining, though, and ultimately a terrific spot [for a Danish health insurance company].
I shot a spot with a river otter in it [for Rapala]. The [animal] didn't cooperate. He ended up shredding [the trainers] arms to the point where we almost had to take him to the hospital. I thought we weren't going to come back with anything. It was only by adding stock footage that we were able to come up with a spot.
The client decided they were not as in love with the concept as they were a few weeks earlier. We were on location in the middle of nowhere in the midst of shooting, and the client wanted a completely new concept. In hindsight, it is funny; but at the time, it was horrible.