I really dislike it when you're goin' down some stairs and you get to the bottom, but you think you have one more step to go and you hit the ground expecting one more stair, then you're all disoriented from it. I think if you have something unpleasant to tell someone, that the exact moment that they're stair-disoriented is perfect to spring it on them, as they'd be somehow magically bewildered enough not to get upset and you totally get away with whatever the unpleasant news was.
I base this theory fully upon science.