I upvote comments: that provide useful information; that I agree with, and writing my own comment would only be clutter; that I disagree with, but think is well

I upvote comments: that provide useful information; that I agree with, and writing my own comment would only be clutter; that I disagree with, but think is well-presented. I downvote comments: that fairly strongly don't add anything to the conversation; that contain a high percentage of profanity without saying anything useful; that I disagree with and are not well-presented (e.g., trolls). But not always. Most comments I don't do anything with. If I see a moderately insightful comment with 1 point, I'll probably upvote it. If I see a similarly moderately insightful comment with 4 points, I may think that's high enough and leave it alone. If I see a moderately trollish comment that's at -3, and I didn't think it was that bad, I might upvote it, not because I like it, but because I think -2 is sufficiently low. On the whole, I try to vote such that the more I want to see similar comments, the higher the score; and the less I want to see similar comments, the lower the score.