
A worshiper crowns a standing stone with a wreath of flowers.
A worshiper sets a pewter unicorn on top of a standing stone.
Which of these two is the worthy offering?
Here's how you determine worthiness: focus. Does the offering enhance, or does it detract? To rephrase: what do you see first?
When you approach the standing stone crowned with the wreath, you see the standing stone. In fact, your appreciation of said stone is enhanced by knowing that someone else has venerated the Stone by giving it a gift.
When, however, you approach the standing stone with the unicorn statue sitting on top, you don't even see the standing stone. Because the human eye is drawn to the anomalous, what you see first is the unicorn. The stupid little geegaw has reduced the Stone to mere platform.
The wreath stays.
The unicorn, though, has got to go.
(The lone exception to the rule against setting something on top of a standing stone that I know of: When you sacrifice to a standing stone, it is acceptable to leave the severed head of the sacrificed animal on top of the Stone. This, by tradition, is counted as an enhancement, if a terrible one.)
It's the heart of pagan worship to treat the icon as you would treat a person. To crown someone with flowers is an act of honoring.
To put a pewter unicorn on someone's head is not even to be thought of.