I nominate as the all time worst: “Da Vinci Code”. When I figure out it’s mirror writing before the esteemed cryptographer, Houston, we have a problem. Also they traveled through two, maybe three, countries and had multiple drawn out episodes in the space of one night–starting AFTER midnight. Plus the entire plot was dumb, and the research was laughable.
More recently: “The Goldfinch”. I know, I know. But they were horrible, horrible people, especially the girlfriend beating best friend.
Anything by Ian McEwan or Gillian Flynn. Ian McEwan for his “Bobby coming out of the shower on Dallas” plot twists and Gillian Flynn for such unlikeable characters.
LOL regarding the* Da Vinci Code*. I couldn’t believe how bad the writing was, and that I kept reading it. It made me so mad at myself. And yes, the mirror writing was obvious to me. Ugh.
The one that made me angriest though was the have it both ways ending of The French Lieutenant’s Woman
Anything by Junot Diaz.
You’re a better person than me, @garland – I couldn’t stomach either “The Goldfinch” (and I liked her other novels!) OR “DaVinci Code.” I made it about 1/3 of the way through them both before I quit.
Life is too short to read crappy books.
As for me, I can’t read anything by James Patterson. Barely made it through Ruth Ware’s “The Woman in Cabin 10” – I hated it. I don’t know why I even finished it (see personal rule, previous paragraph) but I should have thrown it across the room into the trash.
A friend who read a lot loved Jodi Picoult. I bought two of her books – one for her, one for me. Got both autographed at barnes & noble. Slogged through the first ten pages then dropped it in the garbage. Slow uninvolving creaky plot mechanics. @garland – I know you’re a writer – why not give bad books the same test we get – if the first 3 chapters (or 50 pages) don’t grab you, stop reading.
A Man Called Ove
Couldn’t finish it.
Uh-oh: I just started The Goldfinch. This does not bode well for me.
I don’t know if Swamplandia! made it on bestseller lists or not. It did receive enough acclaim/buzz to get me to pick it up. MISTAKE! Throwing it across the room wouldn’t even begin to express how much I dislike that book.
The Poisonwood Bible. I thought it was wretched.
I couldn’t finish A Man Called Ove either.
“50 Shades of Grey.” 
@Classof2015 and @scout59 --that’s a good question. Sometimes l will wait for a book to redeem itself, and then get unbelievably angry when it doesn’t. For instance, I think “The Goldfinch” was written well overall, but allowed its characters to be jerks, without ever really calling them on it. Plus the heist section toward the end was incomprehensible. With Da Vinci–I expected a light read to start; it took just a couple hours to finish it, so again, by the time I realized it was never going to acknowledge its dumbness, I skimmed to see where it was going.
But, overall, point well taken. As I get older, I am much quicker to give up on a book.
This was not a “best seller” per se, but “Mermaids in Paradise” by Lydia Millet was a pretty good book that had the most enraging, incomprehensible, unjustified plot turn on the last page that I have ever read. Be forewarned!
And just to show how taste is personal, I love Junot Diaz, espeically “Oscar Wao”, and really enjoyed “A Man Called Ove.” 
My ex BIL said he wanted to throw “Disgrace” (by J.M. Coetzee) down the stairs after he finished it. My sister and I agreed. The writing is superb but the main character is despicable. I felt similarly about “Dinner” and “Summer House with Swimming Pool” by Herman Koch.
@garland I totally agree with your 2 choices - Da Vinci Code and The Goldfinch. The Goldfinch was so self-indulgent and way longer than it needed be. A good editor should have cut a 1/3 easily out of that book.
Personally, I loved A Man Called Ove.
My nominations:
Franzen’s Freedom. Another plodding, way overwrought novel. I did enjoy The Corrections, however.
The Ferrante series. Yes, I did suffer through all 4 books and wish I had that time back. I should have quit after the first one but some people I usually trust for recommendations loved them so I kept hoping they’d get better and I kept reading. Ugh. No bueno.
"@doschicos --we are reading twins! yes to both your nominations.
“The Alchemist” or really any book by Paulo Coelho…
I also thought “Gone Girl” was terrible. “Da Vinci Code” is kind of like pork rinds. You know it’s bad (and bad for you) but you eat it anyway. But “Inferno” was so stupid I skipped to the end.
BONFIRE OF THE VANITIES!!! I hated it, but had to read to the end to see what happened. (Pre-Wikipedia; now I could have just read a plot summary online.)