The truth doesn't always work. Many many years ago I witnessed a poor member of ground staff address a frustrated group of passengers during a particularly bad winter storm to tell them that there would be a delay of around an hour because they had run out of de-icing fluid. With that a rather viscious individual got up and shouted 'why don't you f
k off down to Halfords and get some more then!
I laughed so much I cried
