You don't need to be a politics junkie to realize that on average, politicians seem to get things wrong at least as often as they get things right. Boom & Bust, Recessions, Crime Rates, Exchange Rates, Financial scandals, environmental disaster... politicians aren't getting the job done. Why?
The problem with running a country is that everyone who does it is entirely unqualified for the job. Every new president or prime-minister is having his or her first go at it. There are no 'practice' countries for people to have a go with before they try doing it for real. Theory is great, but experience is better...