Friction is both helpful as well as harmful:
Friction is Necessary: It reduces the efficiency of work done. Nothing would be able to move without friction. Friction is how things accelerate. Without friction we would not be able to walk, we would just be slipping. Without friction we can not give better performance in sports. Examples: athletes use spikes and footballers use studs to have appropriate friction while they run fast.
A Gymnast uses lime powder on his/her palms to perform many activities like horizontal bar, uneven bar, Roman Rings. In Badminton, players are usually seen to rub their sole of shoes with lime before going to tlhe wooden court. It is done to provide better grip on the floor so that one can move safely. Kabaddi players rub their hands with soil for a better grip of the opponent.
Friction is an evil: It is an evil because it results in energy wastage. Due to friction we have to spend lot of energy and money to make things move and make life move on. Wear and tear happens because of friction. In cycling, there should not be more friction between the road and tyre of cycle. If there is more friction, there will be more energy wastage of the rider. In cycle and motor mechanics we use grease to reduce friction to increase efficiency. In roller skating there should be less friction for better performance.
Therefore friction is both a friend and a foe.
