"Don't walk like that" -- when I have (very, very slightly) crooked hips. My mother was pretty sure I was just walking slightly off kilter just to bother her.
"Don't eat like that" -- I'm still not sure what I'm supposed to "eat like," but my mom decided I had to eat next to her rather than across from her at all times so she wouldn't have to look at me
"Your legs are too skinny" "Your thighs are too fat" "Your belly's too fat" "Why are you so skinny?" "You're going to get flabby arms some day, too, so don't be too happy with them being skinny now." "Your breasts are too big." -- turns out she thought she was being funny (I was VERY SKINNY as a kid, but my body image was all kinds of messed up because I had no idea how to take her conflicting messages; later, she was slightly jealous that I "developed" in ways she never did.)
"Don't slump. Pull your shoulders back or you'll get scoliosis like your aunt." "Don't stick your chest out!" -- My dad was a little off on his biology, too
"Cut straighter. You're a terrible cutter." -- those lefty safety scissors don't make it any easier, folks, particularly when you're lacking in depth perception. Also, this is really unimportant, but it was a HUGE focus for my parents for some reason.
"Why are you so much like your father?" "Why are you so much like your father's sister?" "Why are you so much like (other family members on father's side)?" There's this thing called genes, and I really wouldn't have preferred to resemble my dad's family so, but that's just how these things happen sometimes.
Pretty much everything I did or didn't do with regard to building friendships was open season, as were things like my skincare routine, which I'm pretty sure will NEVER be good enough, even if I'm following the advice of a half-dozen doctors and dermatologists I've seen over the years (for whom the right answer is not always "more Clearasil!").
My mom just wanted us to be better at life than she'd been, and we've mostly cleared up our issues, but she sure had a LOT of things to complain about when it came to me as a child, and dozens more to add to the pile once I became a teenager.