Overshoot

If you command a motor to move 100 mm and it travels to 108 mm before settling back, that is 8% overshoot. Some overshoot is often the price of a fast response; zero overshoot usually means a slower system.

Whether it matters depends on the product. A room slightly too warm for a minute is irrelevant; a positioning stage that overshoots can crash into a hard stop, a dosing pump can deliver too much, and a pressure system can trip a relief valve. Overshoot also grows with integral windup, large setpoint steps and loops tuned with small stability margins, so it is a useful early warning that a loop is close to oscillating.