When I was in my twenties, my flatmate and I wore the same dress size, so occasionally used to lend each other clothes for dates or events. It was great until the day I tried to borrow a burgundy sheath dress for a works do. We were the same size, but of quite different...distributions.
On her it looked very smart and professional. I looked like Jessica Rabbit's brunette sister had decided to try office work.
(I did later wear it to go on a date. 
)