There is an old joke claiming the Thermos is the greatest invention of all time, trumping fire and the phone, even though all it does is keep cold things cool and hot things warm.
The punch line:  Yeah, but how does it know?

When you speak to an audience you can either be oblivious, a thermometer, or a thermostat. But how will you know?

If you are overly self conscious, as you speak, there is a chance that your listeners could get up and leave and you might not
even notice.   Intense fear and anxiety focuses your attention on your intense fear and anxiety, amplifying it.  It is almost impossible to connect with your audience in this state.

Becoming a thermometer  is the first step to connecting with your audience.  As a thermometer you notice whether you are getting a warm, lukewarm or cold reception.  You are learning to read your audience and probably concentrating on the one or two people that look confused or confrontational.  Rarely are the furlong faces a result of what you are saying. Most likely their
grimaces stem from something that happened to them before or something that might happen after your presentation.

As a thermostat, you control the temperature of the audience by reading the collective body language and speaking complete
thoughts to audience members, one at a time, until they nod their head in understanding.  Nodding heads are the best way
to adjust your audience’s temperature.

Focusing on one person at a time, when you speak will take you from tepid to terrific which reminds me of a soup tasting joke.