The most helpful rule of English Grammar

While writing, I ever wondered about the right forms of words to be used in a sentence. I still grapple at many places. But one rule has helped me the most in clearing many of my doubts:-

" The noun or pronoun following a preposition or a transitive verb has to be in objective or accusative case"

The above rule makes the following sentences correct:-

1. The wrath was unleashed on him.
2. Let him and me decide.
3. I want to excel like him at the Olympiads.
4. Life moves fast without us ever realizing it.
5. He, including me, is at fault.

Isn't it fantastic?