The best threats are threats unstated.
Anyone can threaten violence, physical or emotional, and anyone can deliver. However, the mere threat of violence lacks the art, the finesse, of an unstated threat.
Once you’ve explained what you’ll do, cards are on the table. The person threatened can acquiesce to your wishes or accept clear consequences. But with unstated threats, you leave the imagination to fill in the details. And the imagination always supplies something worse than you could ever say out loud.
This is why I never explicitly threaten. Now: turn around, and walk away. I’ll only tell you once.