I *rarely* let myself be photographed. Recently my wife and I were given a portrait session with a pro photographer as an anniversary gift, and I was very uncomfortable in front of the camera. I got through it okay, but the best shots are the ones where I am *not* looking at the camera (IMHO). See, I have eye problems that make it hard for me to look in the same direction with both eyes, and I'm a bit self-conscious about it.
Periodically I take a self-portrait... usually these are full-length shots taken of interesting reflections that happen to include me. But there was once a difficult year when I was simultaneously 1) finishing my bachelor's degree and 2) getting divorced. During that time I did a series of studio self-portrait head-shots using my 4x5 Calumet. So they're very detailed shots, you can see every bit of stubble on my face. I used high-key lighting, with the main light from one side, and when I look at them now, I can really see what kind of shape I was in. I wasn't eating, I was smoking (!) which i don't do now, my cheeks look sunken... I generally weighed around 130 pounds when I was in my twenties, but I got down to 110 during the worst of it... I showed these photos in my portfolio class that last semester and the other students were amazed by them, including one comment about a particular shot, that looked like I had captured myself in the moment of death. I don't have these scanned and I have a hard time showing them now but it was really worth doing, as it did indeed help me through what was a very tough experience.