Mechanical clocks were invented in the northern hemisphere by inventors who were trying to make models of the sun's movement in the sky.
To watch the sun from the northern hemisphere, you have to face south. Then the sun will rise on your left and pass over your head to set on your right. Since the hour hand on the clock was made to follow the sun's motion through the sky, it moves from left to right over the top of the clock - clockwise. The hands are actually modeled after the shadow on a sundial.