Why is subjective beauty so important? This is not an easy question to answer. It is driven into us before we can understand language. The moment a person sees a newborn baby girl, it is mere seconds before there is a comment about how beautiful she is. From the moment a child does understand language she is inundated with messages about external appearance. The messages come from both men and women of every race and culture. This type of thing often leads to an unhealthy obsession that is unsustainable.
No one stays beautiful forever by the most common and gross metrics. That means there is something wrong with the metrics. To be sustainable, beauty has to be more than skin deep. It has to include health, and attitude, and total self-possession. A lot goes into a person. If the only thing you notice about yourself and others is outward appearance, then you are missing out on what makes a person truly beautiful.
This is not to ignore the physical. We are all given one body that has to last us for a lifetime. We are born with some features that we can do nothing about. That cannot be the definition of beauty. There are also the features that we can shape and adjust. While we wrestle with redefining beauty, we should also redefine how we achieve it: