Here is a tricky sentence construction that might catch you by surprise. Look closely at the grammar of this sentence and see if you can detect what’s wrong: She is one of those persons who makes a decision quickly and then acts decisively. The problem here has to do with the antecedent of who and the consequent number of the verbs makes and acts, and if we rely solely on our ear to espy pitfalls of grammar, we’ll find ourselves taking the long way home.
The word who is a relative pronoun, and a pronoun (when it’s not asking a question) always points to an antecedent, a word that goes before it (the literal meaning of the Latin behind the term) and to which it refers. Pronouns and their antecedents like to stick close to each other in English, so there is a general expectation on the reader’s part that the last-named noun or pronoun will be the one the upcoming relative pronoun is referring to. Thus, if we examine our example only up to the relative pronoun, we can see that three words, she and one and persons, precede who: She is one of those persons who. The juxtaposition, though, of persons to the relative pronoun who makes it certain that this is its proper antecedent.
The antecedent of a pronoun determines the number (singular or plural) of the verb with which it works through the relative pronoun, so reading the phrase persons who, we know that the next verb we see, barring any digressions, will be plural because persons is plural. If fact, we find here instead that the two verbs referring to persons, makes and acts, are each singular—singular verbs of the simple present tense regularly add the letter s. This now points to the answer to our problem. The author has mistaken the antecedent of the relative pronoun, likely thinking that it refers to the singular she, the logical subject, and not the plural persons. We should, then, revise the sentence accordingly: She is one of those persons who make a decision quickly and then act decisively. Now both the grammar and the logic are designed meaningfully.
Why logically meaningfully? Because the author did not intend to say that she makes a decision quickly and acts decisively, or he would have said just that. Instead, he has asserted that the subject, she, is one of a group of people with certain emulous managerial characteristics, thereby implying that her habits are not merely idiosyncratic, but typical of an identifiable group and so all the more worthy of credence; she stands with others in these skills, and so her stature should be the greater in our eyes. The author is stating a richer, more complex idea, and has employed (albeit faultily at first) a more complex sentence structure to reflect that complexity.
The practical point to remember here is to always keep your eye on the clauses of a sentence when you want to examine it in some detail. A relative pronoun marks the presence of a subordinate clause, and is therefore always part of a complex sentence. Somewhere, then, there will be a main clause (she is one of those persons), and that main clause will supply information to which a subsequent relative clause is related, both grammatically and logically. Without this more controlled analysis of clauses, sentences are often just too large and unwieldy to be meaningfully considered at once in their entirety.
The further effect in feeling and emotion that sentences make on the reader is a subject more properly examined by rhetoric than by grammar or even logic, and the tools and manner of rhetoric’s analyses are quite different. It is best, both as a writer and a reader, to regard the three arts of grammar, logic, and rhetoric as instruments to be orchestrated, separate upon analysis but harmonious when composed.