As a path into the consciousness of their character, actors leave breadcrumbs for audiences. One method is to develop a psychological gesture, or a repeatable, physical tell. It could be pulling at a strand of hair, twisting a wedding ring, or facial tic.
However, we often see unintended psychological gestures in speakers. The same ring-spinning, hair pulls, hand-wringing, rocking and leg-crossing gestures can connote nerves, lack of preparation, insecurity, or even worse, deception. These gestures draw the attention of audiences and clients.
One should never be self-conscious, or the habit becomes ingrained. Instead, be present and self-aware. So that when a tell surfaces, you'll recognize and release it from your behavior. Practice and mindfulness make it easier to arrive at a state where you are unaffected by your inner critic, and can focus on your intention and message.