Red, the color of human blood, symbolizes passion, fire, love, and anger. In Eastern cultures, it also connotes luck and prosperity. Red occurs throughout nature, from dying stars to dying leaves, and humans have evoked its powers for everything from politics to sports.
Warm colors, like red, orange and yellow, appear to move forward towards the viewer. Our eyes are attracted to them first. An easy way to make your image three-dimensional is to have a red or orange object in front of a blue background. Movies do this all the time.
Colors need to be in harmony. There are a zillion ways to analyze this, but as a photographer you have it easy. What looks good is good. Colors tend to be harmonious when you have two colors balanced from opposite sides of the color wheel.
Warm colors, like shades of red, tend to get the viewer riled up- compared to cooler colors that tend to calm us down.