When I was growing up in Minneapolis, non-fast food milk shakes and malts were both lumpy, with lumps of ice cream and partly mixed liquid. That's the way I like them. They were not of uniform consistency.

I dislike the current milkshakes (and malts, if I can find them), which are so thick that the spoon stands up in them and so thoroughly blended that they may as well be made of pure soft-serve ice cream.