You just did. You couldn't not.
Why it happens. The brain doesn't easily process negatives. To reject an image, it has to build the image first. "Don't be nervous" plants nervous. "Don't drop it" plants dropping. "Don't worry" hands someone the worry, gift-wrapped.
Watch it wreck real moments. A coach yells "don't hit it in the water" — and the ball dives for the water. A parent says "don't spill" — and milk goes everywhere. You told them exactly what to picture, and the body follows the picture, not the "don't."
The simple fix. Say what you do want, not what you don't. Not "don't be late" but "be here by 9." Not "don't panic" but "breathe slow." Name the target, not the disaster. You steer people toward whatever you make them see.
This reaches into everything — parenting, leading, coaching, even the way you talk to yourself. Every "don't fail" you whisper is a picture of failing. Point your words at the outcome you want, because whatever you say out loud is the thing that gets built behind the listener's eyes.