I want to preface this rant. I appreciate diversity and competition. Also, I'm not just an MS or Apple hater. If they make a great product I'll consider using it. I try to look past brands and use products that solve problems well.
UI design is all about disclosing information. Shapes, proportions, perspectives, colors, reactions and transformations! There are infinite ways to go about expressing ideas when speaking the language of design. In order to prevent a colosal goat fuck of a UI, each expression must be executed judiciously.