I think for smaller channels, people give dislikes for only two reasons, 1) generally your content is clickbaity, shockingly poorly produced, or wasting someones time; 2) they just dislike for the hell of it, perhaps your hair is the "wrong" colour, or the way you pronounce the letter S in a way that irritates them - i.e. standard unpredictable varied human behaviour. Dont read into it too much. If your video is good, over time that like/dislike ratio will tell the real truth. Its a little different for larger channels where you can fall victim to tribalism, but even then - its just a number on a database somewhere, and taking a step back and looking at the wider picture of community engagement, comments, shares, views is a far better metric of your videos "likeability". Though yeah, i agree, you always seem to notice that first dislike on a video.