The opening lines. Standing in a line. Waiting.
Expectations can be primed and steered by the opening line.
Generally those first words tell us whether to carry on reading, continue to listen, or at least wait for the second sentence.
But in conversation natural is best. Contrived pre-prepared opening gambits seem good beforehand, but the opportunity to use them in a flowing way rarely occurs.
Everything benefits from spontaneity, every moment.
No harm in some “rehearsed spontaneity” to get you started. But it must come from you.