Well first, don't copy and paste this
Colors come in a variety and can mean different things. We associate each color with a different emotion and colors themselves has meaning in their own right. Such as how Purple is the color of mystery and royalty, or how Red is seen as the color of passion and determination. Looking at different colors can set off emotions within you based on what emotion your brain associates with that particular color.
If you see the color Red, you might feel a twitch of anger, if you're already angry one would say that you are "seeing red", because red is associated with anger. When looking at the color blue you might feel sad or the saying "you're feeling blue", because the color is typically associated with sadness. If you see yellow, you might be happy or feel happy because the color yellow is associated with happiness. They're are many more examples but these are the most recognizable.