Many years ago ships were being overloaded in Europe and sank as they crossed the Atlantic. A guy named Plimsol had the idea to paint a line on the side of the ships hull. The ships were to be loaded until the line was at the waterline, and no more, to ensure they were not overloaded. This solved the problem.
When your responsibilities equal your capacity, you can’t do anything else – it’s all you can do to keep up. When they exceed your capacity, you are going to sink. When they are less than your capacity you have the ability to be spontaneous and even take on more.
Are you at your Plimsol line?