SEO is constantly changing. With bounce ratio attacks and companies selling links, it just gets more and more interesting. If you are going to become an SEO expert you need to be a non-linear thinker. If I were to ask you what half of 13 is, how many answers could you give me? Most only have two: 6 and a half and six and a half. I can think of many more: 6 and a half; thir, teen; 1, 3; one, three; and endless other combinations.
My feeling is that in order to truly understand Search Engine Optimization you must be in it for the pure love of the science. I am extremely successful in SEO and I rarely find others who can comprehend the basics, let alone the finer points.