Friction inside the shock absorber is reduced by having a smooth surface inside the cylinder or by having oil inside the shock absorber. Friction in a shock absorber can cause wear and unwanted heat that can damage the shock absorber. The less friction inside the shock absorber the better it would work. The more friction inside the shock absorber the more stress is forced in the shock absorber and the vehicle. Friction is also a major factor in a shock absorber and important to have the best response and safety.
Shock absorbers reduce shock caused by vehicle motion.
Shock absorbers distribute the weight of the vehicle. Viscosity is the degree to which fluid resists under an applied force. Certain levels of viscosity can change the response of a shock absorber. Damping is a very important feature in a shock absorber. Damping controls the amount of fluid that goes through the damper to the other side of the shock absorber.