My current video got record breaking likes and comments from people saying it should go viral, amazing production, etc. it still got one dislike. I saw that and said, "who is the one jag off that did that??" Other videos with likes, though not as many, have no dislikes, so it was clearly someone who just wanted to do it because the video was breaking out.
I've always said a video with several dislikes is a bad video, many dislikes is an attacked video (unfortunately) but just one or two dislikes means you hit a jealousy nerve with someone. They saw your greatness and it reflected their own shortcomings so, a good video gets a dislike or a hateful comment.
I'd only dislike a video if it's offensive or so poorly produced its unwatchable but it's takes 2 clicks to dislike and leave. But just one to leave and I'd rather save the energy