A while ago the boys and I were up by the playground and we passed a mom picking up her kids from the after-school program. In the maybe thirty seconds we could overhear them, as we went by in the opposite direction, the mom told the kids not to do three things, framing all of them in terms of the dire outcome she feared. "Don't walk on the curb, you'll fall." "Don't run!" "Watch out in the parking lot, you'll get hit by a car!"
Now these were big girls—middle and upper elementary school—and they didn't need correction like that anyway (and I noticed that they didn't much listen either). But even if they were little, I think there might have been a better way for the mom to frame her suggestions.
There's a strand of thought in Christian circles, which may or may not derive from the writing of Derek Prince, that suggests the existence in our lives of blessings and curses. I don't know a tremendous lot about the matter, but as I understand it the theory is that our words have power. If, for example, you announce that you get lost every time you try and drive downtown, it might increase your chances of poor navigational results in the future. Or, more seriously (and maybe more realistically) if you tell your kids in a moment of frustration that "nobody in this family ever amounts to anything" you might really prejudice their chances of future success. A blessing, obviously, would have the reverse effect: "You're going to do great on the test today, honey!" will, in most cases, be useful encouragement to the little test-taker.
Whether or not you buy all that, I think it's worthwhile for parents to consider just why they're including these predictions of doom in their directions to their kids. Do they think kids won't obey without a reason? I suppose it's possible. But even then, it's possible to give justification without wishing bad results on your offspring—or at the very least denying them agency for their own feelings ("You need to wear your jacket. You're going to be cold!"). I have been known to say to my own kids, in that very same parking lot, "be careful as you walk here, the drivers aren't always paying attention." Which is true, and probably explains the mom in the first paragraph's fear. But I try to leave open the possibility of rational consideration, and try not to make ridiculously improbable predictions.
Because that's maybe the worst of it: the girls were wicked not going to fall off the curb, and I don't think anyone's ever been hit by a car in that lot (praise be). So the mom wasn't just negative, she was flat-out wrong. And if one of her kids did fall off the curb, what would her response have been: "I told you so?!" I can't imagine.
So put yourself on the same team as your kids—as anyone you talk to—and don't predict that bad things will happen to them if they don't follow your advice. Tell them your thinking, sure: "that wall is very high and the ground at the bottom of it is hard and sharp; if you fall it will probably hurt." But maybe hold back on the curses.