For driving, the side mirrors should be adjusted so that the quarter panel is just out of sight - you have to move your head just a bit to see them. This gives maximum field of view of traffic when driving. When you parallel park, you move your head and sight down the side of the quarter panel where you can clearly see if it is coming close to hitting anything.
You cannot do this with stock Gen 1 & 2 manual mirrors. (With electric mirrors you can achieve these two functions HOWEVER you have to reposition the mirrors for close parking.)
Look at any hyper car and you will see what I'm talking about. There is a reason they have "wing" mirrors that hang out about 12 inches.