The principle of least action ...

Mirror, Mirror

The principle of least action defines just how lazy reality truly is when viewed through the lens of the two laws of thermodynamics where energy is neither created nor destroyed, only transformed and ... in any closed system, said system always goes to the state of maximum disorder (entropy) because the arrow of time rules. 

The Principle of Least Action says that, in some sense, the true motion is the optimum out of all possible motions, The idea that the workings of nature are somehow optimal, suggests that nature is working in an efficient way, with minimal effort, to some kind of plan. But nature doesn’t have a brain that is “trying” to optimize its performance. There isn’t a plan. It just works out that way.

As the system evolves, q traces a path through configuration space (only some are shown). The path taken by the system (red) has a stationary action (δS = 0) under small changes
in the configuration of the system (δq).[21]

Other takes on this principle include Occam's Razor or the Law of Parsimony ... pluralitas non est ponenda sine necessitate, “plurality should not be posited without necessity.” and Einstien's classic 

Lest we forget. :)

And, of course, Dizzy.

Less is more. 

Addendum:

 BRT waxes poetic about design and nature with The 2nd Law. 

Chaos and the Law of Initial Conditions also apply to the Principle of least action without question.