Why hand-set stone reads differently
The difference between rock placed around a pond and stone set the way water and geology would have left it.
You can usually tell within a second whether a water feature was built by someone who thinks about stone. Nobody can articulate why. The reasons are specific and learnable.
Grain runs the same direction
In natural outcrop, bedding planes run roughly parallel. When boulders are dropped in at random angles, the eye reads it as debris rather than geology, even in a viewer who has never thought about rock in their life.
Stone is buried, not perched
Rock in nature sits partly in the ground. A boulder set on top of grade looks placed. The same boulder buried a third of its height looks like it has been there since before the house. It also doesn't move.
Scale varies deliberately
A ring of similarly sized rocks around a pond is the single clearest signal of an amateur build. Real formations mix a few large anchor stones with mid-sized supporting rock and gravel filling between them.
No liner is visible anywhere
Carefully placed stone protects the liner and gives the feature a natural finish.
The waterfall is tuned after it's built
Water finds the cheapest way down. Getting a drop to sheet, split, or chatter the way you want takes running it, watching it, shutting it off, shimming a stone, and running it again. That iteration is most of what separates a stream that sounds like a mountain creek from one that sounds like a garden hose.
Every stone gets looked at twice. Plenty get set twice. That is the whole method.