Yellow is a cheerful, warm colour that is most commonly associated with the sun.
Because of this association, it is often considered to be a happy colour and has given rise to the expression "mellow yellow", meaning laid back and relaxed.
Bright yellow has an extremely high visibility, and as such is extremely ideal for drawing attention.
In ancient China, the legendary first emperor was known as the Yellow Emperor or Huang Di. The imperial family of China at that time were the only people allowed to keep anything that was coloured yellow. This is because of the colour’s clear association with the sun, and therefore glory and prominence.
Although it can work as the primary color, yellow often works best as a companion to other colors. Use bright yellow to create excitement when red or orange may be too strong or too dark.