If you are demonstrating that your latest model has a fantastic crash-preventing piece of technology, the last thing you want is for it to completely fail when you are showing it off.
This story almost makes you feel sorry for Volvo. They had lined a load of international journalists up in front of a test to show how their technology recognises an obstacle in the way and brakes automatically to avoid it.
Except it didn't. The car (piloted by a crash-test dummy and not a driver thankfully) ploughed straight on its merry way into the back of the truck that was parked in the way for the demonstration.
To be fair to Volvo, they didn't try and put a spin on the matter, and just held their hands up and said that they didn't know why it had failed. Red faces all round.