Ergo, these two sentences should pack the most punch/make the highest impact possible (as everything in between serves to support these two points of emphasis).
One sentence paragraphs are also possible, but there's a special kind of attention drawn to these, and so they should be used sparingly and carry enough weight to stand on their own.
Though you have some creative license when it comes to structuring paragraphs in fiction, the overall idea that a paragraph should develop a single concept remains. A shift in thought, topic, or conversation should result in a shift in paragraph.
Otherwise, a paragraph is going to reflect your writing style, and while it may be tempting to lean toward a longer, more involved collection of sentences, readers today like their white space, and the more compact your paragraph is visually, the less tempted they will be to pass it over.
Be Brilliant!
~Katie~
