Bad for the Boobs: Shapeless
Honestly, I don't know if this style really suits anyone, well endowed or not.
I mean, really, who wants to look like a bowling pin? That said, if you want an excellent costume drama series on the rise of the fashion house in the 1920s you can do no better than House of Elliot. I highly recommend it, but I digress, we were discussing shapelessness.
1927 via The Costume Institute of the Metropolitan Museum of Art; Drop Waist 1925 via The Victoria & Albert Museum
T-Shirt Dress Byblos 1965
I include both T-shirt dresses and drop waists in this category. I remember reading and enjoying some frivolous little contemporary romance novel in high school. Until the very end where, at the most romantic moment when the hero is about to return home to find the heroine waiting for him at last . . . she puts on a T-shirt dress. I was crushed. The whole novel was ruined for me. Ruined I say!