it doesn’t have to be your favorite book or anything. It can be any book that you find yourself thinking of with a sense of pride for having read it.
Personally, I am really proud of myself for not DNFing A Little Life and pushing forward. I read a very good chunk of that book with tears running down my face–mind you, I was reading it on my phone during lectures for the entirety of my first semester last year–and I was always on the verge of putting it down just because of the horrible content. Also, it was pretty long; too long, actually. So when I was done, I was simultaneously Heartbroken, broken (just like in general), and relieved. It was truly a feat.
An honorable mention is A Tale of Two Cities by Charles Dickens, because I swear to God I did not understand a single thing about it even 10 chapters in. Charles Dickens is too much.
I accidentally stayed up all night reading it back in 2001. The next evening, I had tickets to see Depeche Mode. Their opener for that tour was Poe, touring the Haunted album, which is based on the book - the singer is the author’s sister.
I did not know this at the time, and it was certainly an experience to wander into on no sleep and surrounded by 18,000 people