Small spaces such as bathrooms or hallways — or even small kitchens and offices — can be a great place to experiment. I recently made over my very tiny bathroom (Before & After to come!), and the best part was the transition from pale purplish-gray paint to a strong blueish green. The bolder color makes me happier, and, because it highlights the tall-ish ceiling, it actually makes the room look bigger.
The key to making the look work is knowing your limits. You'll want adequate light; natural is ideal, of course, but not necessary. As in Images 1, 7 and 10, it's important to balance out color and pattern with neutral white or cream. You can also break up a strong color with pattern or artwork (Image 8).
1. Flickr user Ninaribena1 licensed via Creative Commons 2. Design*Sponge 3. Heather's Coral Kitchen 4. Elle Decor 5. Living Etc. 6. via Absolutely Beautiful Things 7. House Beautiful via Aesthetic Oiseau 8. Lindsay & Jeremy's Mindfully Merged Space 9. Design Crisis 10. Ferm Wallpaper Gives Home Office Depth