One of my favorite things about sack dresses is how absolutely enormous they are. They don't skim your skin, but instead balloon in places and create contrasting proportions. So when people mention that they are so unflattering, I'm like, "au contraire mon cheri" because the contrasting proportions are great for downplaying problem areas — like hips, or out of shape legs, or maybe a bloating belly from a Memorial Day Weekend at the pool with food and drinks. Here's the thing though: if you're going to wear a sack dress, you have to be sexy somewhere else. That means show some skin, wear some heels, lipstick...something. Otherwise, it becomes too covered up to be flattering.
KAAREM dress (size small) also this one and this one, J. CREW denim jacket, MADEWELL sunglasses, J.CREW sandals (size 8, run small), NARS matte multiple lipstick/blush