There are billions of words- yet there is only one correct word.
Whether in the fields of Oklahoma, or in the deserts of Saudi Arabia, writers know that one right thing to say.
Happy, elated, joyous, cheerful, blissful.
They all mean the same thing, but connotatively, are worlds apart.
I was happy for his success. I was elated over my success. I was joyous at the party. I was cheerful during the Christmas season. I was feeling blissful during the wedding ceremony.
Without conscious word choice, the world would a very sad and monotonously gray place indeed- rather than a beautiful spectrum of color.