"It is of course well known that careless talk costs lives, but the full scale of the problem is not always appreciated. For instance, at the very moment that Arthur Dent said "I wouldn't want to go anywhere without my wonderful towel," a freak wormhole opened up in the fabric of the space-time continuum and carried his words far far back in time across almost infinite reaches of space to a distant Galaxy where strange and warlike beings were poised on the brink of frightful interstellar battle.
The two opposing leaders, resplendent in their black jewelled battle shorts, were meeting for the last time, when, a dreadful silence fell, and, at that very moment, the words, "I wouldn't want to go anywhere without my wonderful towel" drifted across the conference table. Unfortunately, in their native tongue, this was the most appalling insult imaginable, so the two opposing battle fleets decided to settle their few remaining differences in order to launch a joint attack on our galaxy, now positively identified as the source of the offending remark.
For thousands of years the mighty starships tore across the empty wastes of space and finally dived screaming on to the planet Earth - where, due to a terrible miscalculation of scale, the entire battle fleet was accidentally swallowed by a small dog. Those who study the complex interplay of cause and effect in the history of the Universe say that this sort of thing is going on all the time. "
-The Hitchhiker's Guide to the Galaxy