Stop signs were yellow until 1954 because up until then, red dye would not fade over time.

Red is a color that gives life to the human face by making the circulation of the blood transparent. In just this way it animates all surfaces where it appears, and enlivens all the harmonies in which it plays a part.
Red is matter, brutal and heavy and always the color which must be fought and vanquished by blue and yellow.
Red is the first color a baby sees
Some colors can induce hunger. This is true for red, yellow and orange
Red doesn’t really make bulls angry; they are color-blind.
Red is the most potent of hues. If there is one electric blue, a dozen reds are so charged. One can use them to punctuate white, burn into bronzes, or dynamite black.
Red is the most territorial of colors. It protects itself. It stakes a claim and is on the alert against the spectrum.
Red is a color tha occupies a place between the liveliness of light and the quiet of dark colors. It thus has an expression of dignity, magnificence, and pomp.
Lobsters are not always red. About 1 in 5,000 North Atlantic Lobsters is born bright blue.