Facebook reach-around.
When you comment on a Facebook post, get a 'like' from the person who posted it, and then they comment on your comment, which gets a 'like' from the person you commented on.
You comment on a post. The poster 'likes' you. Then they comment on your comment. The person you commented on 'likes' that comment.
You say 'That's the dumbest thing I've ever heard.' They 'like' you. They say 'You're the dumbest person I've ever seen.' The person you commented on 'likes' that.
You say 'I hate this post.' They 'like' you. They say 'I hate you.' The person you commented on 'likes' that.