I love reading and finding out what other people are reading. As a rule, I try to finish a book once I get past the couple of chapters. But at some point, I have to cut my losses when it seems obvious I don't understand or enjoy what I'm reading almost halfway through. I wish I'd figured this out years ago with Crime and Punishment and Waiting for Godot. I quit reading Brideshead Revisited and Portrait of the Artist as a Young Man twice. Maybe it's just me, but I think James Joyce is the most overrated author next to Ernest Hemingway.
It might be interesting to find out what books would make folks here say "Naaah" after starting a book and deciding it's not be worth the bother.
Be fair. Don't put books you had no intention of reading. And tell us what finally made you decide you'd rather watch paint dry on the wall.