When you create new layers of abstraction between the thing or event, you are becoming more meta.
For example: A footnote that is needed to explain another footnote is meta.
The problem with being meta is that if you add sufficient layers of abstraction or complexity between the original event and the convenient abstractions you create to clarify or explain it, you eventually lose all connection to the original. Generally, you need no more than two or three levels in writing.
Too much meta in your writing leads to meta fog
In writing, this means your writing sucks
Man, I need notes to explain the notes to my notes for my thesis!" - "That's very meta. Perhaps you should rewrite it?