It's a cultural thing, and directly related to wealth (or class, if you prefer).
If most people work outside for a living, then the sign of wealth is that you don't have a tan. If most people work in offices, then the sign of wealth is that you have a tan, implying that you went on vacation or otherwise have the available leisure time.
When most people do manual labor, having impractically long fingernails demonstrates that you don't have to do that.
When most people have two or three sets of clothing, changing clothes several times a day demonstrates your wealth.
When most people eat a subsistence diet, being fat is demonstrating wealth. when most people eat fast food, being thin demonstrates your superior resources.
If most people need to pay attention to what they are wearing at their jobs, dressing in a way which signals that you don't have to pay attention is a status marker.
If everybody drives a car, picking an unusual vehicle can be a status marker. What's the difference between a Chevy Silverado 2-door and a Ford F-150 SVT Raptor? They demonstrate different spending priorities.