Ask HN: Have you up-vote someone you disagreed with today?

I feel like there's been an interesting shift in the comments recently: not in their quality, but in how the community is reacting to them. What I've noticed is that there seem to be a growing number of light-dark-light-dark-light threads. That is, a comment voted down, followed by a response voted up, followed by a riposte voted down, etc.

Perhaps it's not my place to say, but I've always been under the impression that comment votes are there to evaluate whether the comment adds to the discussion or not. Votes should not be a measure of whether you agree with the point. When I see long threads of alternating up-down voting in comments, I think one of two things is happening:

1. Individuals are voting based on alignment of views.

2. People are responding to comments that don't add to the conversation.

If there is a long chain of follow-up comments, it seems self-evident that the comment added to the discussion, and probably shouldn't be voted down. If you feel that a comment doesn't add to the discussion, vote it down and move along; no need to reply.

So the question: when was the last time you up-voted a comment you disagreed with, but which added to the conversation nonetheless?