Success........

Behiend of Success is Difficulty.
Something difficult is neither easy nor impossible. It requires skills, effort, attention, but still the result is not guaranteed.
"Difficulty" is a key concept for a new economics, because mainstream neoclassical economics distiguishes only what feasible from what impossible, without allowing this intermediate category so relevant in reality.
People face difficult tasks, thus have to cope with them by learning, technology, social networking, etc. To a large extent, the fact that acquiring information, elaborating it, delivering a proposal that matches conflicting criteria are all difficult tasks constitutes the rationale for bounded rationality and its simplifying routines.
In another vein, there is an important relation between difficulty and motivation. A slightly more difficult task than the present skill level would guarantee is particularly motivating: too easy or impossible tasks are less motivating that challenging tasks.