When I am searching for power socket format used in Europe, I came across an interesting article on origin of driving direction. Some countries drive on the left hand side of the road, which is Japan, UK and its former colonies, and the rest of the world drive on the right hand side. Driving on the left hand side actually makes sense and it can be dated back to pre-automobile days. Knights are usually riding on the left side on the road, so that their sword using arm is closer to incoming enemies. Moreover they carry the sword on the left hand side, so it is easier to mount or dismount the horse from the left. It is more natural to get off the horse to the side of the road rather than towards the center of the street. Thus riding and driving on the left hand side of the road is a symbol of the noble class, where the presents leave to walk on the right side of the road. When revolution came in France and US, the people want to distinguish themselves from the old royal system, therefore driving on the right became the rule. Sometimes illogical choices due to political ideology would stay and affect our life for a long time.

The article can be found at this link.