People are basically visual creatures. They are easily turned on by what they see. The outrageousness of the design, graphics and colors teases their sense of sight. It sends excitement and thrill that generates more appetite to stare longer and be charmed.
Among design, graphics and color, the latter is the most difficult to show accurately. This is because color perception can be affected by lots of factors. First, it depends on the structure of a persons eye. The viewer may be colorblind. Colorblindedness may vary. It can be either slight or acute. Another factor is the impact of one color to another when placed side by side. This can happen either through reflection or visual illusion. How do this happen? To make a clear notion, you can practice this: hold a bright red colored paper or object right next to a white piece of paper. Do this near a sunny window. As you can observe, the paper turns into a pastel color of red which is pink.
With regards to printing services, colors vary. Colors may not match especially if you use different printing services, some may use CMYK while others prefer Pantone colors. Colors may also vary between presses. It depends on...