Even an inch can make a difference.
One inch is the reason why the jacket on Betty Draper (left) does not work. That extra length is like a giant arm pushing you out of the way of what could have been a great outfit.
A fashion cock-block.
See? See how it hits Betty at the widest point of her hips? If it was shorter like the one on Lily Collins (right) - then you would had have the sultry look that the turquoise skirt by Roland Mouret demands.
Bad, bad Betty.