Because of this, clonidine is often used to treat the symptoms of drug, alcohol, and nicotine withdrawal. Clonidine is beneficial in opiate withdrawal because it treats symptoms that are commonly associated with that condition (watery eyes and nose, diarrhea, irritability).
However, Friction can also be harmful, for example, Rubbing two objects together causing friction causes heat, under the right circumstances it could even cause a fire, so in that case it could be good or bad, when you rub two sticks together to make fire, its good, but lets say your engine in your car is low on oil, the friction in the cylinders will eventually cause the motor to over heat and seize up and then you have engine failure and a large mechanic bill, thats bad,
Sliding friction is stronger when an object is stationary (this is called static friction) than when the object is in motion (this is called kinetic friction). When trying to move a box, it is often harder to get the box moving than it is to keep the box in motion.