It's rare that narrow and functional come together in one sentence! In this case, I've found a few narrow but functional spaces to share with you.
There's something about a living room being narrow that makes it feel impossible to entertain. It's all about the layout. Move your furniture around and find a sense of flow that works for you.
Make use of what you have! Creating storage and extra seating or a day bed can make any narrow guest room / office work for you.
Narrow bathrooms are pain, but are totally functional! Here the motto is less is more!
Babies don't take up much space, but their things do! In narrow spaces, it's important to have necessities only.
Narrow kitchens can still be "open". Make use of all the wall space you have and create as much functionality by keeping the walkway empty.
A balcony can go from standing room only, to very roomy with a simple bench seat.
How do you make your narrow spaces functional?