|This essay contains the advice or opinions of one or more Wikipedia contributors. Essays are not Wikipedia policies or guidelines. Some essays represent widespread norms; others only represent minority viewpoints.|
Rhetoric has little use anywhere in Wikipedia, and should always be used with extreme caution.
The Ancient Greeks distinguished rhetoric, the art of reasoning persuasively, from logic, the art of reasoning correctly. Both were considered admirable accomplishments. Wikipedia is different. As an encyclopedia, Wikipedia is concerned both with accuracy, so logical thinking and writing is always encouraged, and also with neutral point of view, so in the text of an article rhetoric has no place at all.
A difficulty arises because nobody wants either the discussion or the articles to be boring either. The line between rhetoric and good interesting writing can be hard to draw.
In articles, one answer to this is to use the wit of others, by including quotes from authorities in the field. However this brings the danger that these quotations, if persuasive, can be used to support a point of view. One answer to this is to be aware of your own point of view, and to use quotations from those who take the opposite stance. This is far safer than quoting those whose views you share. You are unlikely to quote them in such a way that the view you do not hold is promoted.
In namespaces other than the article namespace, humour is widely appreciated, but needs to avoid being personal attack. If a joke is at someone's expense, the question to ask is, Will the victim think this is funny?, and if you are not confident that they will, avoid the joke. Jokes designed to disempower an opponent are good rhetoric, but poor wiki etiquette and contrary to Wikipedia policy.
This principle can be applied far more widely than just to humour. One aim, perhaps the main aim, of discussion here is to build consensus. So is your wit designed to empower those of the opposite view, helping them to see more clearly? Or is it designed to disempower them, forcing them back into a hole? It's hard to see how you can answer both questions yes or both no, they are mutually exclusive. So if you can answer either, you've probably identified whether or not your contribution will improve Wikipedia.
The difference between a prejudice and a conviction is you can explain a conviction without getting mad. – Marginal note in Readers Digest.
See also Wikilove.