The letter nobody writes
Almost everyone intends to write it. Almost nobody does.
Not a will. That is a different document, and it handles only the parts a lawyer can handle. The other one. The one that says what you thought of someone, what you hoped for them, and the things that were too large to mention at dinner.
We assume it is understood. Often it is. But understood and said are not the same thing, and only one of them can be read again later.
Who would yours be addressed to?