Driving Basics

As the flair says, It is a rant. But who is teaching the drivers that overtaking from left-hand-side is the correct way to do it? Why do they think it is their right to overtake from the passenger side of a car? Why do two-wheeler drivers think that driving in the center of the road is the safest? Why do people who have to take right turns on traffic lights stop their vehicles on the left side?

WHY?