I've been knitting lots of hats lately. I've no idea where the camera is, and no motivation to take pictures of them, but at last count I have completed three hats in as many weeks. I have six more in progress at varying stages of completion.
While I still despise knitting scarves, I'm finding that hats are a good way of using up all my sample skeins and remnant balls of handspun yarn that I keep for sentimental value. Not only are stripes colorful and fashionable on hats, but my CDO (like OCD, but the letters are in alphabetical order, like they are supposed to be) doesn't kick in quite so bad when I'm knitting hats.
As I see it, a scarf should be fashionable, or warm, or soft, or at least pleasant-looking enough that you're not ashamed to take it out in public. All a hat needs to do is fit on someone's head. The fact that there's only a half row of fuzzy pink yarn on a hat project seems an appropriate way to use the yarn and add color--but if it were on a scarf I'd feel the need to rip it out if I didn't have enough yarn to repeat the stripe at the other end for "symmetry."