It would be fine to base design on a great quest for perfection if Web design and sofas and buildings were bounded by a large chain-link fence that divided designed objects from people. But in our world, people and objects are all jumbled together. People, ugly and fat and appalling as they can be, are going to sit on the sofa you make. They are a necessary component of the design process, and the design that ignores them and their real lives is not design but fetishism.
Go mess, go!