Most weak shots down the middle (by competent penalty takers that aren't a bag of nerves) are a conscious reaction to the keeper moving to the side the player h

Most weak shots down the middle (by competent penalty takers that aren't a bag of nerves) are a conscious reaction to the keeper moving to the side the player hoped to slot his penalty. If the keeper doesn't move, the ball is comfortably stroked/smashed past him on that side.