What do your lower ball joints do when they are going bad?

As the vehicle sits at rest the wheel might tip out or in a little. Most people wouldn't even notice it. But when being driven the lower ball joint would let the steering knuckle move laterally and even up and down over hard bumps. This would cause the wheels alignment angles to wander in and out. The vehicle might pull one way then all of a sudden pull the other. As it wears even more the steering may feel loose side to side, as the wheels are tipping from steering wheel input. When the wear reaches a critical point the joint can separate or even break causing sometimes catastrophic steering failure.