Why does it bother us if someone else doesn't like what we like?
What if you truly enjoyed a singer... a singer that you learned about entirely accidentally, and a singer who was generally without fame. Indeed, it seemed that nobody else liked them at all, and the people that you played the singer for were all unimpressed.
One day, you see their videos on YouTube have scarcely a few hundred views, most of them have a majority of thumbs down, and what few comments do exist on them are entirely negative.
It might be enough to lead you to question y our own judgment on that singer. Are you somehow wrong for liking them? Do you like them for the wrong reasons? It may even be the case that you would question whether or not you have a good ear for music.
I've always found thinking about these things to be kind of disturbing because it calls into question some of our basic ideas about popularity, what is good, what is bad, etc.