Occasionally I read something I don't like. Usually I learn something because of it. Sometimes I figure out I don't like it halfway through, finish it, but then imagine a better ending.
Who decides what is required? That doesn’t make any sense. You can recommend awesome books to your friends (have you read Meditations by Marcus Aurelius?) but they are not compelled to do so.
If I see books on your recommended list that I either liked or hated I may be more or less inclined to read your recommendations, but calling a book a “must read” is egotistical.
I think when people consider something required, they either mean they wish it taught in school or have a belief that it is profound enough to recommend to everyone. Like, I have a Marxist-Leninist reading list that I made and linked in my profile, and would love for more people to read it (or, more specifically, the works on it) but I can't beam it into people's heads nor force them to engage with it. I can only recommend it for those who actually want an ML reading list.
I am referring to that which has a widely accepted cultural meaning. That which a large part of society knows and/or not knowing it will make you outside the general culture. This varies in space and time and is not decided independently by anyone, it is rather a consensus between creators and the public.
You can not read it, but you must know it or you will be left out of references that others know, impoverishing your experience.
Piranesi is fantastic and I will always recommend it, for those wanting enjoyable fiction. There's a lot of Marxist theory I think is critical too, but I can't distill that down to one or two works.