I upvote comments I like and downvote comments I don't like. This is independent of whether I'm replying to them. The one exception is when I'm arguing against

I upvote comments I like and downvote comments I don't like. This is independent of whether I'm replying to them. The one exception is when I'm arguing against the comment, in which case downvoting feels like bad etiquette as long as the other comment isn't clearly harmful.