Just did one of these last week. First issue was that I am quite tall and the photographer was quite short, but he didn't have a step (presumably for health and safety reasons), so to get the angle right he asked me to squat a little. Second issue is that he asked me to take off my glasses to avoid any reflection, but my antique glasses are an important part of my appearance (early-20th-century intelligentsia?). Third issue is that he asked me to show my teeth, but I never show my teeth when smiling (thanks to the NHS I have what the Americans call "British teeth"), so not knowing quite how to show my teeth when smiling I think I ended up baring my teeth instead. The overall effect being an uncomfortable unfamiliar unseeing grimace. I'm hoping great things will come of it.