Good Design = Research + Design + Test.
I thought I wanted to be a mathematician when I grew up. I dreamed of going to MIT and solving math problems all day long. This dream died when I took Geometry and was told I would be spending my days proving theoretical concepts that were proven thousands of years ago.
As an adult I became a designer. I spend my days solving real-life problems that impact lives. It turns out my childhood dream of problem solving was not that far off. I discovered I would rather solve the types of problems that I face every day.
In school, I was taught that a word's definition cannot include the word in question. This would cause a paradox that would require you to know the definition of the word to define the word. However, a similar concept does exist in math, a recursive function. Good design is like a recursive function in that good design is continuous and loops through itself to continually improve. There is no good design that has an end point or it will eventually become bad design.