Suppose that an executive branch administrator pens a letter of intent, that says they interpret the law a certain way.
Now this isn't actually _binding_, but it's a strong indicator of how you'll be treated.
Maybe you can get the courts to reverse it.
Suppose an administrative agency is tasked with setting and enforcing standards. And you don't like the standards they've set.
Can the court overturn the standards?
No.
This is called Chevron Deference, the principal that the court must defer to agency interpretations.