"Prolix! Prolix! Nothing a pair of scissors can't fix!", sang Nick Cave on 'We Call Upon The Author' from 2008's Dig!!! Lazarus Dig!!!. Judging by this article on the art of omission, the New Yorker's John McPhee would agree.
He notes that "Writing is selection" - choosing what to include or retain and what to leave out or remove. Paring down your prose to improve it is a skill that appears to have been drilled into him through the process of "greening" at the behest of his editors: "the idea is to remove words in such a manner that no one would notice that anything has been removed". The consequence of tight word counts for magazine and newspaper publication, such rigorous excision is perhaps becoming a thing of the past given that websites don't suffer from the same pressures for space. Nevertheless, it's a skill that writers would do well to learn (myself definitely included) - not least to show rather than tell, or to allow the reader the creative freedom to make sense of things themselves.
One thing McPhee doesn't explicitly say is that it's much easier to edit down someone else's writing than your own. There's something about being so close to the words that means you often can't see the wood from the trees - either that, or (as is often the case with me) you can just be a bit too precious about your phrasing.
(Thanks to Adam for the link.)