I just watched a video of myself doing some public speaking, and it was painful. I remember thinking, just before I began to speak, that I should not start with “Um,” and yet it was the first thing I said. I didn’t realize how little conscious control I had over that kind of thing. Likewise, some people have weird physical mannerisms while doing public speaking (like standing on one foot) that I think they’re unaware of. Seeing or hearing recordings of yourself, though embarrassing, seems the best way to become aware of this sort of thing in order to change it.
Jeff’s band has a practice of recording all their performances and listening to them on the drive home. He’s found that most musicians hate doing this and avoid hearing recordings of themselves because it’s so unpleasant to hear mistakes. But he attributes much of his band’s improvement to their practice of learning from their recordings.
I sometimes see people wearing unfortunate clothing and wonder if they’d have chosen to wear it if they could see what it looked like from behind. I assume I have clothes that look worse than I think they do, because everything looks better when you’ve just adjusted it and are holding yourself just so in front of a mirror. For people seriously into self-improvement, I wonder if you could run a service that takes candid photos of people so they can see what they look like at random moments. But I think hardly anyone would be willing to pay for that kind of ego hit, even if it helps them improve.