It shows up before the presentation. In the quiet after you gave hard feedback. In the pause before you say the thing you actually mean.
It tells you that you are not ready, not enough, not the one to do this.
Most of the time, you believe it.
Here is what I have learned after thirty years of sitting with capable, accomplished people. The ones who struggle most are rarely the ones lacking talent. They are the ones who handed the microphone to a critical voice and forgot they were allowed to take it back.
I call that voice your Inner Bully.
You were not born with it.
