I reviewed novels for the Otago Daily Times for a number of years. The literary editor of that august newspaper was an intellectual snob of the first water and flatly refused to read novels. I was continually schmoozing around his office looking for books to read and eventually I began to get them by the carton load. I wrote reviews for over 2000 books in seven years; about 200 of the reviews were actually published - which gives you some idea of the editor's values. Most of them wound up at the local library, although I probably still have some 30 or so that I kept. You got to keep all of the books on the condition that you sent back the copy of the reviews to the publisher. Which I did, religiously.
The vast majority of the novels fell into the mediocre to mindblowingly bad/boring range. One of the worst was Mitchener's Aztec. I picked it up and put it down, picked it up and put it down and on and on for weeks. Several times I was tempted to simply review it off the dust jacket, something I'm sure that Wow will agree is not exactly uncommon. However, I persevered and eventually finished it and wrote something like "will be interesting to those who like exhaustive historical detail of dubious quality and would rather not have to sift through too much of that boring plot stuff". When I sent the review back, the person at the publisher who was responsible for these things sent me a thank you note back with all the other NZ reviews of Aztec attached. They were almost ALL literal reproductions of the dust jacket blurb ... I'm still not sure exactly what the message there was meant to be.
The very worst book it fell to my lot to review was a self-published effort by someone whose name I mercifully forget. It was a science fiction-y type of thing and was deadly dull because of the hackneyed plot and was diabolical to read because of the turgidity of the prose. The distributor sent it to the paper asking that we have a look. My review was scathing, and I thought that the distributor would take a very dim view of it. Instead, I got a whole box of self-published efforts to review. Most of them were pretty bad, which is probably a tribute to the publishing house book selectors' capabilities. But that first one was the absolute and utter worst I ever had to contend with.
Having said all of that, however, there were many gems amongst the dross. And they were anything but hard work to read and review!
