CLICHE NUMBER ONE
"I don't want to argue about it."
The preceding sentence is often uttered, ironically, by the person who started the argument in the first place. It is seldom uttered at the very beginning of the argument. Rather, it is usually uttered after the person who says he or she doesn't want to argue has already spent some amount of time arguing. Yet, it subtly implies that arguments themselves are inherently bad, and that the person making the statement is too mature to argue about anything, unlike the other party involved in the argument.
My response: "Sure you do. If you hadn't wanted to argue about it, you wouldn't have made the stupid and highly debatable statement that started the argument, and you wouldn't have continued to defend that statement. What you don't want to do is lose the argument that you started. Now that you can see that you are losing the argument, you want to end the argument without conceding defeat, so you try to misrepresent things in such a way as to imply that I am an excessively argumentative person, when the fact is that I am no more argumentative than you are. I just make better arguments, that's all."
There is another category of people who "don't want to argue about it", and that's people who are so full of themselves that they think everything they say should be taken as gospel truth just because they are who they are.
CLICHE NUMBER TWO
"You just think you're so smart."
This statement is usually uttered because the person who utters the statement has run out of intelligent rebuttals to the other person's arguments, so he or she is trying to change the subject by implying that the person who has won the argument handily is guilty of egotism.
The way I've phrased the statement here is usually the way that little kids express things. As people get older, they come up with other, more sophisticated ways of saying essentially the same thing.
CLICHE NUMBER THREE
"That's your opinion."
Well, of course it is. Most arguments are about opinions, unless they're about verifiable facts, and even then, they're also about opinions concerning what those facts are. But the issue isn't whether or not it's an opinion. The issue is which of the two or more competing opinions is best supported by the facts and by solid principles of reasoning.
When you argue about something you believe to be true and the person with whom you're having the debate says, "That's your opinion," then you can be fairly certain that the person has run out of good rebuttals for your arguments, because saying "That's your opinion" does not amount to a rebuttal or an argument.
CLICHE NUMBER FOUR
"Opinions are like bodies. Everyone has one."
The preceding statement is evasive, in the sense that it's completely irrelevant to the question which is currently being debated. Saying that everyone has an opinion is not the same thing as saying that all opinions are equally valid or that all arguments are equally persuasive. The implication of the statement is that there's no point in debating the issue because there is no good way to determine which of the competing opinions is the most likely one to be true. But that's seldom the case.
The four cliches listed above all seem to have more or less the same objective, which is to end further discussion. They can also be a way of saying, "This argument is going nowhere. There's no way we're ever going to agree, so let's end the discussion now."
Sometimes it's necessary to end an argument, but oftentimes, people end conversations and arguments prematurely because they can see where those conversations are heading and they want to try to avoid or postpone defeat. Such people often go to great lengths to impugn their opponents while simultaneously avoiding any real discussion of the specific points their opponents have made.
People are particularly likely to end such debates when they have made up their minds to do things which are irrational and which have the potential to hurt others. They cannot defend their decisions logically because those decisions are inherently indefensible. Therefore, they refuse to intelligently and objectively discuss the merits (or lack thereof) of their decisions.