Here is my theory as to why races tend to be run counter-clockwise:
Those of us with left to right written language like to see things move left to right. When a race is run counter-clockwise, the near side of the track moves left to right, and we are pleased. Knobs tend to move clockwise because we look at them from above. Therefore when they move clockwise, the near side is moving left to right.
Anyone know if any of these things are often reversed in countries with right to left language?