Why people get sick

When I was a schoolboy I liked Karlsson from the book by Astrid Lindgren. And He said that everyone wants to get sick,
because you lie in a bed and don't do anything, but resting. But I think that sickness is not cut and dry.
The modern pace of living very fast, people don't have time to stop on a minute.
Sickness it's a organism's reaction to its way of living. [The time of sickness it's ]awkward phrase.  maybe try [The time one spends being sick is] time to think. You should stop and think about your life, and what's wrong in it.
Maybe you don't need to rush. You'd better hold your horses and savour every moment of living. [nice idiom!]

Suggested correction

Why people get sick

When I was a schoolboy, I liked Karlsson from the "Karlsson On The Roof" series of books by Astrid Lindgren. He said that everyone wants to get sick, because you get to lie in bed and don't have to do anything other than rest. But I don't think that being sick is all that cut and dry. The pace of modern life is very fast, and people don't have time to stop even for a minute. Sickness is an organism's reaction to its way of living. When you become sick, then it's time to stop and think about your life and what may be wrong with it. Maybe you don't need to rush, but rather to slow down and savour every moment of living.