A coworker suddenly appears and asks you something, what should be an easy answer for you. Their stance, tone of statement, and their glaring eyes tells you that they need a reply as soon as possible, like right now.
The request is simple, but your mind suddenly goes blank.
Or you begin to say something and then suddenly stop mid flow, having a momentary mental block. Everyone takes notice and looks at you, wondering why you’re stalling.
You’ll at times say something which is close to what you want, but …