Though I would never shame anyone, there is a benefit to reading "bad writing." Careful analysis of what works is as important as studying what isn't working in a piece. Sometimes I just abandon books, but other times, I push through and finish. I want to know from start to finish why I think there are problems. I do this in order to avoid it in my own writing.
I look at consistency - in writing, in the characters, in the plot, and in simple facts/research. One author I know didn't do any kind of research in her books. Simple facts were blatantly wrong. It was sad.
I look at the author's tone. I've read several books where I just didn't like the tone. It was off-putting. One male author really liked to use big words from a thesaurus. It seemed just like middle school writing where kids throw in big words without really understanding the meaning or understanding the effect that the words have on readers. He was pretty obnoxious.
I look at the craft of writing, especially at the sentence level. One very famous author could tell an interesting story, but her work was full of incomplete sentences. I couldn't really feel the same level of respect for the works after a while.
I look at the point of view that the story is told from. Another popular book was off-putting in the POV, and I skipped through and read only the last few pages. I was unimpressed. I have read a few books written from the second person point of view. I didn't enjoy it. I felt like it was a barrier to enjoying the story in a fluid read.
The last thing I've noticed is verb tense. Present tense is popular right now with many popular books. I find it hard to follow on occasion. I know from experience that it's harder to tell stories with present tense than past tense. As a reader and a writer, I've stumbled and fumbled with present tense. It's not a good feeling.
All in all, writing is personal. Writers must make many choices, but it's as important to give the reader the kind of experience you want them to have as it is to stay true to your craft. I don't know any good writers who actually want readers to struggle with the mechanics of a writer's choice in crafting.
Do you purposefully continue reading something bad? Let me know in the comments. What do you notice in bad writing?