Robert Heinlein ... I give the man props for being a good writer.. but he has two chief habits that bug the crap out of me. First, half of his heroes are wise old guys with long lifespans who make out with hot young servile women. Since Heinlein WAS a "wise" old guy with a long lifespan, it gets a little sickening after the third or fourth book about it.
Examples: The cat who walks through walls, Stranger in a Strange Land, any book with Lazarus Long in his older years.
My second and related complaint is his standard method of staging a scene where Dirty old man sits around and expounds wisdom to Young Man Seeking Guidance. These scenes typically span the lengh of three chapters, interspersed with other spear carriers and messengers stopping by to agree with Dirty Old Man. If you find a Heinlein book without this scene in it, please let me know.
It might help at this point to mention that I think Heinlein died from some kind of degenerative brain disease.