two guys working in a bomb factory where they suppose to pack 10 bombs in each box for delivery. boxes were designed to hold only 10 units. at the end of the night while packing the last box they realized that somehow they had 13 bombs left and only one box. so they decided to squeeze the 3 extra units in the same box. while trying to fit them all in the same box, they put little extra pressure on them, as a result, somehow one of the unit generated enough heat and exploded, followed by the whole box explosion, followed by the whole factory explosion. killing them both and many others in the factory.
moral of the story:
most of the accidents can be prevented by making sure everything is done properly and in the right manner.