Why did the authors of the constitutions set up the checks and balances?

The framers of the Constitution created a system of checks and balances so that one branch does not have too much power over the others. Each branch of government checks the power of the other branches. For example, after Congress approves a bill, it also has to be approved by the president, but if the Supreme Court believes that the bill is unconstitutional, they are able to overturn it. This system was created so that one branch does not grab all of the power and take control of the country, like we see in dictatorships.
Look at it this way. If every grower in the country plants nothing but corn, the overall health of the people will plummet rapidly.