You don't need to use a word like quiescent to describe a lonely Saturday morning You don't need to use a word at all, let alone a pretentious one You don't need to use a word for how you feel when you can just stare blankly ahead You don't need to use a word to express loss or heartbreak or the devastation of time but happiness is another story entirely:
Jubilation notwithstanding the possibility of succinct impressive diction can represent one's joyful self in the morning as one explicates to one's mirror some magnanimous memes some serendipitous sentences some fortuitous phrases spoken aloud - in gratitude more than one ever grasp, envisage; You need those words.