I found a video on Upworthy that does exactly that: showing people that the parts they are self-conscious about are exactly the parts that make them beautiful and unique.
"I'm really self-conscious of my round face, especially my cheekbones", one man says. He doesn't know that a stranger is standing behind the mirror and, without hearing what the man is saying, remarks: "He has really nice cheeks!"
Click the video to see the whole experiment for yourself.