I just can't seem to get my head around it. Why do people hate going on photographs so much? Is it insecurity? Afraid they won't be photogenic? Because in my opinion, whether you are photogenic or not depends entirely on the photographer.
A photograph is subjective, and therefor, everyone can be photogenic. Communication between subject and photographer is important. Unless the subject is a rock.
I suppose it is different for spontaneous shots, but there, when the fear of the camera is not involved, there is no problem. Again, when you know you're going on a photograph and you find it scary, just communicate, take your time to feel ready.
I, for one, love going on photographs even though I have a clearly visable disability that I will always be reminded of. I love the whole process of going on a photograph, too. It doesn't matter if you are imperfect, because nobody is flawless. That's the beauty of it.