A comedian you think is not remotely funny they think is hilarious. So what?
A book they read they loved which you could not get through beyond the first chapter.
A restaurant whose food they wax poetic about and you think is greasy salty tasteless
A musician they think rocks that you think sucks
Do you just keep your opinion to yourself or are you very noncommital? "That was very interesting" instead of "what was the point of it?". I dunno.