Those of you fortunate enough to have followed the 2010
saga drama around the claimed proof of P versus NP (by Vinay Deolalikar), must remember Scott Aaronson, who became famous back then. For reasons.... better left untold. I have always liked Scott because he is funny, interesting and among other things, because he also refers to God as "She".
Anyway, he had this to say about Quantum Mechanics :
There are two ways to teach quantum mechanics. The first way -- which for most physicists today is still the only way -- follows the historical order in which the ideas were discovered. So, you start with classical mechanics and electrodynamics, solving lots of grueling differential equations at every step. Then you learn about the "blackbody paradox" and various strange experimental results, and the great crisis these things posed for physics. Next you learn a complicated patchwork of ideas that physicists invented between 1900 and 1926 to try to make the crisis go away. Then, if you're lucky, after years of study you finally get around to the central conceptual point: that nature is described not by probabilities (which are always nonnegative), but by numbers called amplitudes that can be positive, negative, or even complex.
The rest makes a very very nice read: http://www.scottaaronson.com/democritus/lec9.html
ps: His (informal) definition of the Euclidean norm is.... the best I have ever heard! Also, at some point during the text he makes reference to Flatland, that some of my readers will certainly not have heard of, so here we go: Flatland: The Movie.