A few examples of harmful and beneficial inertia.

Inertia – conservation of the speed of a body in the absence of action on it by other bodies
The benefit of inertia:
1) Supporting planets in their orbits
2) Inertia helps to maintain the speed of any object
3) Inertia in a medical thermometer
4) If you kick the ball, then it will continue to fly by inertia
5) When ice skating
Harm in inertia:
1) The bus cannot brake quickly in case of an emergency, which causes accidents
2) In equestrian sports, if the horse stops abruptly, then the rider will move forward by inertia
3) when people stumble
4) Passengers fall during hard braking
5) Splashing water from a bucket