I saw a post for a pillowcase dress for a little girl, and I really wanted one. But... I'm a little too big for a pillowcase! So I made a sack dress. It ended up with drawstring armpits because I cut wholes for the armpits than ended up too big and looking like Vs. So I twisted the Vs to the front and back and I like it a lot better, though now I have drawstring armpits and a seam in front and back.
It was sincerely one of the easiest things I've ever made, took me like two hours.