purely superficial reasons. I was sick of being a skinny twig.
One day I was trying to ask a guy out and he cut me off and shut me down without even letting me finish. That hurt. Then he was a complete dick to me every time I saw him. So I kind of remade myself. Not going to lie it was largely a "screw you" motivation, but I started hitting the gym, choosing better clothes, and chopped off my hair.
In hindsight it's one of the best things that's ever happened to me.