Action was a strange concept in Physics, but it was foundational. It was usually denoted by the symbol 'S' in equations, and it measured how potential energy was converted into kinetic energy along a certain path.
Action was the consequence of a universe that seemed to dislike and penalize potential energy. As if the laws of physics demanded that all potential energy be converted into kinetic energy as smoothly as possible, and the result was the Principle of Least Action. It was a principle that stated that particles, objects, and systems would take the path that converts potential energy into kinetic energy most smoothly, with the least amount of action.
Paths with higher action took more time and distance to convert potential energy into kinetic energy and were therefore inefficient for their purposes.
