My own pet peeve in non-fiction, particularly the kind that appears on blogs: the excruciating warmup before the author finally gets to the point of the post.

I know why this happens. When you sit down to write, you don't know what exactly you're going to say. You may even be anxious about it. Then, an idea sparks your imagination and you start writing stuff. The warmup that comes out initially gets you on track. Nothing wrong with that.

The harm is keeping that crap in the post. Delete it! If I don't understand what I'm about to read in the first paragraph, I'm probably done.

Something else I don't like: writers who use too many words. The telltale sign of a first draft is the vast quantity of words (and even entire sentences) that don't need to be there.

A single edit with the goal of ruthlessly eliminating every unnecessary word works wonders for any first draft.

Edit: On the topic of fiction, the author gives a beautiful example from the Wizard of Oz:

> When Dorothy stood in the doorway and looked around, she could see nothin but the great gray prairie on every side. Not a tree nor a house broke the broad sweep of flat country that reached the edge of the sky in all directions. The sun had baked the plowed land into a gray mass, with little cracks running through it. Even the grass was not green, for the sun had burned the tops of the long blades until they were the same gray color to be seen everywhere. Once the house had been painted, but the sun blistered the paint and the rains washed it away, and now the house was as dull and gray as everything else. [continues]

I haven't read the book but this passage alone makes me want to.