Are microorganisms friend or foe?

I believe that some of them are friend.If we did not have these little things,well i think we would have something bad break out like a new big bad microorganism that would get rid of the human race fast.
Penautjar:)

They can be both, depending on the microorganism. Some are harmful or fatal to humans, and others are essential to life--like the ones that live in the digestive system and make the breakdown and digestion of food possible.

There are of course many dangerous ones, like some strains of E. coli or cryptosporidium of staphylococcus.