Stitches on a Soccer Ball

A soccer ball is not smooth or symmetric.
It has 12 faces that are held together by stitches, which add additional drag onto the ball.
The stitches also affect the center of pressure, which describes the average location of the aerodynamic forces, which typically occur at the center of the ball.
A soccer ball moves erratically because the center of pressure shifts depending on the orientation of the stitches.