>Maybe it's not in vain. Serves several purposes at once - conveys the urgency to the listener, helps the speaker utter something fast without thinking, and at the same time they may ease up a bit after the utterance.
A colleague at work got the Ten Commandments a bit mixed up: "Thou shalt not desire thine neighbors wife in vain".
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
