200 amp service, someone explain what may have happened?

Andy in ATL

Can't I put them at thirty inches deep horizontally? I like it when the plans call for a triangle shaped ground rod configuration. Good magic there. After they are driven, I like to gather everyone in a circle and chant incantations to make the triangle work better.

Andy

Billy Bear

If ground rods are not that effective how come they say only one ground at the service entrance if you have another at a different location such as sub panel or generator you create a ground loop which they say is bad but I have not been able to get a good reason of what's so bad about a ground loop.
Anyone have a reason for this thanks