People want a solution that is simple enough to implement, but complex enough to be useful.
I think this concept applies universally across life's problems. In fact, I think the very definition of beauty and elegance in problem solving revolves around using the least amount of effort to solve the problem.
But what is beautiful and elegant also tends to have this one feature: it has the necessary robustness to stand up to ever-changing conditions of operation while yet maintaining a simple interface. In other words, anyone can use it anywhere, at anytime, to get the desired result.
The best stockbrokers, chefs, pianists, surgeons, marketers, designers, programmers, entrepreneurs, and sportspeople all understand this: that they need to draw upon years of experience and practice to deliver a simple solution that solves the problem that is immediately before them. They are the best because they can wave their magic wand when push comes to shove.
The breakthrough happens when you start thinking like a creator: when you start designing for the person who has every reason to reject your product, and turning him around. It is when you are able to honestly present a stunningly simple solution to a problem, and do it again and again and again regardless of the situation.
That is what I mean by "Simplicity Sells, Complexity Scales"