Question

why is friction a necessary evil?

Answer 1

Friction is considered as a necessary evil as even if it causes  wear and tear and loss of input energy, it is required by us and to sustain life on earth as without it our life would not be possible.So in a nut shell , friction has both advantages and disadvantages and so it is considered as a necessary evil

Answer 2

with out friction we wouldn'"t be able walk ,produce heat energy,come into rest,etc