Explain the statement frictional force is a necessary evil

Nearly every action requires friction such as walking, otherwise we would be falling all over the place or be unable to hold objects. However it also causes wear and tear on the human body and machinery. Think about people's joints getting worn down over cartilage. We need some form of friction to hold the knee but too much friction contributes to the wear-down of cartilage.

which coordinates are the best estimate of the solution to the system of equations?