Probably because everybody just focuses on their flaws and not the great things about themselves and probably to do with the fact society encourages people to be self-conscious about their weight or image... but everybody is different and if we were all the same life would be boring, people need to try and embrace their individually and remind themselves they are beautiful and worth something
I have a heart combined with an infinity symbol on my right wrist, 3 music notes behind my left ear and my most recent one is like an ankle chain around my left ankle which goes down onto the middle of my foot about halfway with a star :)