I've spoken before a thousand several times saying with a straight face "Every audience is an audience of one."

My first example, I was asked to give one more talk on how one needs to shuffle seven times. There were four people, and a blackboard smaller than my kitchen window. I went for it like I was in office hours, which I've always enjoyed more than teaching. A few weeks later a phone call "I liked your talk." "Thank you." "Could you come to Switzerland to give it again? We can only offer a week's full expenses..."

Then I was asked to write a review of the off-broadway play "Proof" for the American Mathematical Society Notices. I didn't read it much, but I was told people do. I worked a very hard week on my review; my Swarthmore College classmate Ben Brantley's Broadway reviews were life or death for productions at the time, and I didn't want to embarrass myself. Ron Howard read my review, went to see "Proof" twice and loved it, and hired me to be the math consultant for "A Beautiful Mind". That was a transformative experience.

Every audience is indeed an audience of one.

https://www.ams.org/notices/200009/rev-bayer.pdf

To imagine a big audience as just 1 person sounds cool, but when I imagine the talks I need to give to a bigger audience, I find it very daunting. I can only hope that I overcome it soon.