Friction is what keeps us from realizing our goals. It is what compromises all of our plans, sometimes making them unrecognizable. It defies our wish for perfection and constantly surprises us with new elements of resistance. It constitutes the divide between dream and reality.But friction is also what gets us moving, a necessary incentive to achieve progress. Nothing can start if it cannot push off something else. By blocking or delaying the easy solution, friction makes for a richer, more varied world. If it stops schemes from being completely fulfilled, it also stops them form going...