Although I can't remember the exact words, the feeling that sentence evoked stayed with me for years.
"Elaine's life was shrinking around her, like a polyester blouse in a hot dryer."
The article came out years ago, in one of those Sunday supplement papers like Parade or USA Weekend, and it told the story of a woman whose fear of leaving her house became worse and worse until she got help. Funny, I don't really remember how the story ended, because that first image, that hook, was so vivid for me. I'm a very fickle reader, but if you throw a good hook my way, you've got me for at least a few pages just out of respect.
Not just for fiction, a great hook can be used in articles, poems, anywhere you want to command attention. When done well, it grabs your reader by the lapels, yanks them in and gives them no choice; they simply must know what comes next.
I suppose my penchant for hooks is why I love the contest at That First Line. The deadline is approaching fast, so if you have a talent for gripping first sentences, go for it.