[TeMPOraL]

You made a very accurate description, though I'd argue that depending on situation and culture, "please" in "please put the gun down on the pavement, or I will shoot!" might not be that much out of place.

It conveys friendliness, the concept of "we're all friends here and we don't want anyone to get hurt, so let us sort this out without a mess"[0]. On the other hand one could argue that abrasive speech is very effective at bypasing various psychological bareers and delivering message straight to the target - after all, that's the reason for so much shouting and insults in the military. So there's a trade-off.

[0] - I guess I might have been watching too much Star Trek in my childhood, which gave me a deeply ingraned attitude that we can all see the bigger picture if we try hard enough.