david copperfield, for example, is an incredibly dull read (imo). but it doesn't actively bother me having read it, and sometimes knowing how it goes comes in handy. so overall i don't care about it but i'm situationally glad i read it
the wizard knight, by contrast, combined poor writing quality with stuff i found highly disturbing in a way that means i can't entirely get it out of my head. literally just the knowledge that i read it is stressful. i regret having read this book
also absolutely do not ever read the wizard knight please learn from my mistake. there's literally thousands of better-written self-insert fanfics you can read online if you really want to, and most of them don't glorify abusive behaviour
honestly a lot of the so-called classics of literature fit this general pattern—most of them are relatively uninteresting to a modern audience in terms of writing style, and the majority of them are useful tools for developing a contextual perspective on the time & place they were written. the downside, of course, is that it's exceedingly common for them to be really d__n disturbing for a modern audience, especially if one happens to be a minority, since the list tends to be curated by white men
i will, however, encourage folx to look into dickens' work if you're not already familiar with it. i wouldn't generally recommend any of his novels, but his short stories tend to be good and it's worth reading commentaries on a christmas carol just for the history—i'm legitimately impressed by the amount of detail he fit into that one story in support of better treatment for the poor, and a lot of it is hard for a modern audience to pick up on. so decent commentary contextualises a Lot of things