Anthropology professor checking in. I find it wildly ironic that today we despise peeling oranges, because when agriculture was adopted in southeast asia ~12,000 BC, oranges didn't have a skin to be peeled (crazy how drastically something can evolve in such a short time) but were bred to have one -- oranges that grew with thicker peels (at this point it was a thin whitish layer that varied in thickness) generally contained more Vitamin C because the white substance was rich in it, and thus was healthier for humans to eat. Humans always loved the peel as the best part, and there are some documented tribes that would just eat the peel and throw out the insides. However, as humanity approached the 16th/17th century, oranges became a symbol of royalty primarily in france because it was exclusive to mostly southeast asia. As a result they didn't know that the healthiest part was actually the bitter peel, and ate the sweet, juicy insides. Over time eating the insides and discarding the peel became a showing of social status because it showed that you got an adequate amount of vitamin C from other meals and didn't need to eat the peel for health. This only continued on until today because as we now know, the insides have enough Vitamin C anyway and tastes better, so we never really stopped.