Why is my small toes, toe nails completly flat like paper?

My small toes, toe nail on both toes is flat. All my other 8 toenails are round. I don't mean flat as in the area that get clipped with a nail clipper I'm talking about the top part of the toe nail. Its flat like smoothly straight flat. My friends think its so weird and cool they can't stop touching my little toes.