A ruffle is volume with a direction, and that is why it is so easy to overdo.
One at the shoulder lifts the whole silhouette. One at the hem softens it. Both at once and the eye has nowhere to rest, because two competing sources of volume cancel each other and the shape disappears. The reliable rule is one ruffle doing something, and everything else in the outfit staying flat enough to let it.
The wardrobe here goes far past that limit, which is useful. Build the excessive version once and the rule will stay learned.
Babs and Friends Back to School