Conan O'Brien at Google: The World Has Completely Changed

That’s very much what I would expect. You generally disagree with someone because you think they have poor arguments – how could something that is, say, factually wrong or not coherent also be insightful? I always cringe when people here say you shouldn’t downvote when you disagree. Should you really not downvote if a comment contains obvious factual errors or if the arguments obviously make no sense? (I have to add, though, that the “obvious” is important here. I think you shouldn’t downvote when someone made reasonable errors in their argument.)

I think there are cases where comments you disagree with can be insightful (when, say, a aspect of a problem is shown that you didn’t consider before) but I would also argue that those instances are rather rare.