Poor writing will make me put down a book. Run on sentences and such. One of my pet peeves is when an author goes on telling and telling. A book has to have some telling for sure, but show me the character in action. I like interesting dialog. I hate dry boring dialog. I like descriptions that are evocative. Don't just tell me the sun was hot and shining. If I see sound effects like "bang bang" or "knock knock" in an adult book, I'm putting it down. If you can't describe someone knocking at the door or shooting a gun, you're not a writer--in my opinion. Everything doesn't have to be at the level of Toni Morrison or E. Annie Proulx, but should at least strive for that level.
