I’ve read all ten volumes of the Malazan Book of the Fallen, twice. Each time took a few months so not particularly quick but they are massive, each book’s around 1000 pages.
I’m a fully grown adult but I still get a mild sense of achievement when I finish any book! 
I love that term!
Not even dinner first?
I can read upside down
Just turned my phone upside down to see if I could too and I can! And now feel proud
Wish I could read properly in other languages, literate in Somali, Arabic and Korean and read at a 6 year old’s level in each
As a veteran of an English degree, I burnt myself out reading Paradise Lost overnight and all sorts of other useless and counterproductive efforts.
Fucking hell yes. Could probably recite the first page in my sleep. Kill me.
I read all the harry potter books in 2 weeks in the lead up to the final one being released when I was about 12. It was summer, I didn’t know anyone near me, and I also think I was sick at during that time period
Read A Little Life in ten days last year. That seemed like a massive feat at the time but it’s nothing compared to everything else in this thread.
Reckon any reading feat in busy adulthood, all my reading accomplishments were from childhood or unemployedhood, its so hard to find time to read when busy. I have a bad habit of reading book previews on Google books and meaning to get them when I like the first 3 chapters but never do, a little life is on this list
Less impressively, I read Snuff by Chuck Palahniuk in one sitting when I was 16 and felt very physically dirty afterwards
No matter how long it actually takes, reading that book would feel like absolute years of wasted effort.
Felt this with American psycho 
anyone tried to learn speed reading? got a book on it once, think I was making a bit of progress but think I like reading at a leisurely pace
Halve your number of books read and this is basically my experience too. Had a couple of very uncomfortable flatmate fallouts when I lived with people from my course 
Can’t think of any other than getting through LotR when I was 11, which felt like a feat at the time. And bragging to a teacher that I’d read a Warhammer 40,000 novel in a day. He didn’t give a shit about that.
Not a feat as such but I read a 220 page book in 2.5 days on a holiday a few years ago. I was racing to finish it on the plane and just made it as we were taxiing in the airport.
I got to about 5 pages left and realised there was no way the story could be wrapped up in time, got to the last page and it said ‘to be continued’. The book was brand new too so the sequel wasn’t even written yet. Bastard
I read The Shining from cover to cover on an overnight flight from Vancouver to Gatwick.
Started a new school when I was 7
Teacher didn’t believe me when I told her I’d read all the set books (Bronze, Silver, Gold books 1,2 & 3)
Got sent to the head on day 1 ‘for lying’
The head gave me an Edinburgh Reading Test for 14 year olds
50 reading comprehension questions, 4-option multiple choice
I got 49 out of 50 right
Thus my reading comprehension at age 7years 7months was equivalent to standard 13year 7months
That teacher did everything she could during that school year to try and humiliate me in front of the other kids 