Because of its warm and happy color, yellow creates a sense of cheerfulness and playfulness. Psychologically, it is optimistic, illuminating and uplifting people's spirits. So if your favorite color is yellow, you have this positive and happy disposition in life.
Since today is valentine's day, let us spread love and lift someone's spirit by simply giving them fresh sunflowers instead of roses. Haha. Why not? Sunflowers are known for being "happy" flowers. They are bright and cheery, and as warm as the sweet summer sun.