Theory:

Let us say you are holding an earthen pot in your left hand and a glass tumbler in your right hand.
 
Do you have any idea which is more comfortable to hold?
 
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A person holds an earthen pot
 
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A person holds a glass tumbler
 
It is more comfortable to hold an earthen pot rather than holding a glass tumbler.
The reason for this is friction. The earthen pot has an enormous amount of irregularities which provides more grip to hold. Whereas, glass tumbler has fewer irregularities, so it offers less grip.
 
Friction is necessary because it is helpful to us in many ways
  • Without friction, we cannot write.
  • The speed of the vehiclecannot be controlled without friction.
  • We cannot rotate the pulley without friction between the pulley and the belt.
  • Without friction, we cannot even take a walk.
shutterstock_219757786.jpgFriction helps us to walk.
shutterstock_186351869.svgFriction between the board and chalk helps us to write something on the board.
shutterstock_1403918891.jpgFriction helps us to hold the objects.