For me it all started when my little brother told me about this book he read and described it to me in such a way that when I actually read that book I was disappointed in it. Although, that's not the author's fault. More cause I was more naive and my brother is such a great liar.
But anyways the first book that got me into reading was Pearls of Lutra by Brian Jacques and is still one of my favorites of the Redwall series. The book my bro tricked me into reading was Taggerung and ironically kind of glad he did. Hence my characters are always anthropomorphic.
Shadowmancer by G.P. Taylor really showed me how to develop characters and helped with my world building along with Harry Potter. Both this book and series showed me how to build tension and suspense.
But a book that really altered my writing style has to be Darth Bane: Path of Destruction. The whole book is about the villain and it was just a thrill to see into what a mind of evil thinks like.
I read Robert Jordan's The Conan Chronicles and that really showed me how to develop action and technique. Also the choice of words is always important to your writing craft. And made me rethink my action sequences.
As for bad books, or well books that really showed me how not to be predictable was
1. Twilight the 1st book cause when Bella was in a dark alley getting some creepy stares from a bunch of guys. I joked to myself, "Wouldn't it be funny if..." Edward showed up out of nowhere and rescued her like a damsel in distress.

whenever I make that joke I feel this.

And 2. Ranger's Apprentice series Kings of Clonmel. I made the joke again and then in the book we learn that Will's mentor, Halt has an evil twin brother. Come on really? Sibling rivalry sure but evil twin it's kind of

Oh, and apparently Halt is actually royalty. I like surprises don't let me guess it before I can even form the question.
One that made me lol recently was Were-world: Rise of the Wolf, apparently someone has Vader issues.

But then he unnecessarily censored a character's gender until halfway through the book. And yet somehow again I guessed it but there really was no need for it. Only that this Were-lord doesn't want his enemies to know that one of his children might be easy to kidnap. It wasn't necessary to censor the Were-lord's kid's gender from the main protagonist.
I think it's cliche that I don't like but it's more along the lines where the author tries to surprise the readers with this

but it ends up falling flat like this...
Though it's not the author's fault or maybe it is for making it too predictable. Or maybe I'm just that intuitive. Haha

Probably not it has to be the writing style.
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