When simple indicative sentences can't drive home our point

MOST of the day-to-day writing that we do consists of simple, plainspoken indicative sentences in the normal subject-verb-predicate construction pattern, as in "We wrote the refrigerator manufacturer about its poor customer service." Sometimes, out of impatience or anger, we make such indicative sentences more forceful by ending them with an exclamation mark: "We wrote the refrigerator manufacturer about its poor customer service!" Then, if the veracity of our declaration is challenged or denied, we feel the need for an even more forceful way of presenting our case or making our point.