The following post from 2014 references an old discussion, but the theme is perennial and I've seen a number of people making the mistake it criticizes in the past few months, so I thought I would put it up again as a PSA.
John Holbo has an interesting post on the difficulty of teaching students to build arguments. He rightly recognizes that the difficulty is actually not related to the intelligence of the students; and rightly recognizes that what gets called 'informal logic' is useless for addressing the problem when it occurs; and interestingly suggests that students are using the "makessense" stopping rule -- they judge whether everything's good in argument-land by glancing over things and seeing that everything 'makes sense', and then stopping. And it's certainly the case that whenever I ask students what makes something a good argument, they will explicitly say that it makes sense -- I ask it every term I teach Intro, and every term it is both one of the first and one of the most popular answers. In practice they are judging things by plausibility of content, not by structure or technique; the standard is not quality of argument but quality of interpretation of experience. This sort of thing is not exclusive to students; in fact, if you read the comments thread on Holbo's post with a sharp eye, you'll see instances of people who clearly think they are building arguments doing exactly the sort of thing Holbo's students are doing. Argument-building is not an instinctive practice, and cannot be a continual one, but is instead an occasional and deliberate one, and it requires even then a habit of seeing one's reasoning as something crafted as well as expressed.
In any case, one of my pet peeves arises in the comments: the view that the primary purpose of argument is to persuade. This is a useless response to the problem Holbo himself is considering (as Holbo himself briefly notes in the comments), because what most typically persuades people is exactly what the students are doing, and this is probably partly why the students are doing it. If anything the problem is that students are shortcircuiting argument-building in favor of what they think has more effect. But more than that, it is simply false. There are legions of purposes that arguments in practice fulfill -- clarify points, state reasons, raise ideas or questions or problems, provide occasions for refutation, show that one has a possible answer to a refutation, show that there are alternative approaches, and so forth -- and most arguments simply don't persuade. What is more, persuasion is clearly an extrinsic feature of argument that depends less on the features of the argument than on the attitudes and assumptions of the people dealing with it; whether any given argument persuades will depend utterly on the context, so it is not and cannot be a stable feature of argument. It's not even clear that persuasion can be an end of argument at all, as opposed to an end (sometimes) of communicating an argument, which is a distinct matter.
This is not new. There is in philosophy a very old name for the view that the point of argument is to persuade; it's 'sophistry'. One of the old Platonic points is that if you take argument to be primarily for the purpose of persuading people to its conclusion, what you are really saying is that reasoning is primarily a way to impose one's will. Someone who has this view is taking their own reason to be merely an instrument for gaining power and manipulating people. In healthy argument, the ends of argument are many, and persuasion is at best merely one of them, or, perhaps, at best merely one of the reasons why you might put arguments forward to someone else.
It's not surprising that it's such a common view. As social creatures we are very invested in persuading people. Further, a lot of our vocabulary and first approximations for handling even technical features of arguments comes from experience in building cases in forensic contexts, where persuasion is certainly a goal. We are also naturally invested in our own reasoning capabilities, so I don't think we can rule out the motivation of liking the taste of victory that comes when someone else ends up having to agree with us because we outmaneuvered them. It is an experience that has considerable salience, making it easy to overlook much quieter purposes of argument.
But I think it is, in fact, one of the most dangerous possible views. It never fails to lead people astray.