Blues can rarely be chosen by looking at a small paint swatch alone. The blues most clients prefer tend to have a gray undertone, which keeps the color from being too airy or too bright, screaming baby boy nursery, or "The Smurfs."
Blue is the most requested wall color besides gray and beige. However, it can change quite a bit according to lighting, so it's best to paint up a large sample to get an idea of the actual color in your space. Keep in mind that blues intensify once painted on all four walls, so a selection that looks blue-gray on a small sample, will likely show more blue once the project is completed.
Unless the homeowner is wanting a "beach vibe," we do recommend warming up a blue room with warm accents such as wood tones, tans, and creams, as blue is a cool-toned color. That said, blue is one of our favorite colors for bathrooms - always calming and fresh!