1. Long paragraphs. Hard to read. Please keep your paragraphs fairly short, and ALWAYS start a new paragraph when someone else is speaking!
2. Long asides, where the writer gives background information. Just stick with the main narrative, please!
3. Writers who introduce too many characters in their stories. Gets confusing!
4. Historical fiction with historical inaccuracies. Do your research first, or don't write about it!
5. And also historical fiction with 21st century political correctness. Many horrible things went on in our past; live with it!