Livelygrey

One of the fun things about colors is that it somehow always seems to reflect the leading view of a certain age or culture. Take the ancient Greek view on color...

Aristotle described color as a quality of material. The surface of any kind of material releases small particles (atoms). The shape of the particles is determined by the kind of material. The particles 'stamp' their shapes into the air. As air consists of tiny layers, the shape of the particles is transferred from one layer to the other until it reaches the eye of the observer. The eye 'senses' the shape of the particles and thus perceives the 'color' of the material.
The role of light was described as making the air 'transparant' so as being able to transfer the shape of the particles.
Interesting view....
So color was a quality of material, not of light. This implies that the influence of the light could and maybe should be neglected when making pictures. Which was indeed the case. Aristotle insisted that artists should never picture shade. A picture should be build up from solid areas of color. Sort of 'color by numbers'. Drawing shades was considered improper.

Interestingly another implication of the Greek view was that statues should have different surfaces for differing materials. On a statue of a man, the skin shouldn't have the same surface, the same color, as the clothes. And this was also indeed the case. For ages it has been assumed that Greek statues and temples were meant to be white marble. But this is a misconception. Originally the white marble was covered with bright colored paints to represent the differing materials. Here's a recent reconstruction of the colors of a Greek statue:
In a way one might say that the ancient Greeks adhered to an idea of 'local' colors. Meaning: a certain color was always tied to a certain place and a certain material. This idea has influenced the European view on color for a long, long time.....

When I Googled "favourite color" I came up with 1930000 hits. The favourite color is apparently a favourite subject. Trouble is: there's no such thing as a favourite color. At least not in the form of a pot of paint or a color swatch.

First: it is impossible for the human eye to consistently identify a specific color. In other words: it is impossible to recognize the same color in different circumstances. Exactly why this is so is a long story on its own. But it involves phenomenons such as matamerism and color constancy.
Or, consider this example:

Which green would you pick as your favourite?
Surprise: the image contains only one shade of green. This pretty much blows the idea of 'favourite color' as an identifiable, unchanging color, doesn't it?

Second: the choice of color depends on how it is chosen. In other words: it all depends on how when and where the colors get picked. In fact a while ago I conducted an experiment in collaboration with Inholland University to test this premise. 30 people (consumers) were tested and interviewed to see how they pick colors. As part of the procedure they were asked to pick a favourite color from a fan deck. In a next step this color was combined with other colors in a set of 3 different color combinations. Then they were asked to pick their favourite combination. In a last step the color combinations were applied in a room and the people were asked to pick their favourite color scheme. Guess what? Only 6 out of 30 were consistent in their color choices. Meaning that their favourite color actually turned up in their color combination and in their room.
As an interesting aside the people were also asked to pick their least favourite color. It turned out that most people are a lot more confident and consistent in picking a color they dislike, than in picking a favourite color.
Obviously, using the Muller formula and other tricks, people can easily be manipulated into picking a particular combination. And when it comes to picking colors for a house, people simply do not pick one and the same favourite color for all the rooms. So why start out with asking for a favourite color when advising people? There must be more important questions to ask...

A favourite color, if it exists, only resides in the brain. It is fleeting. And that is perfectly fine. Until you try to tie it to a specific color swatch. There's this wonderful story of Oliver Sacks who tries in vain the find a color of blue he once experienced in a drugs invoked hallucination. He only encounters it once:
"...Then I went to a concert at the Metropolitan Museum of Art. In the first half, they played the Monteverdi Vespers, and I was transported. I felt a river of music 400 years long running from Monteverdi's mind into mine. Wandering around during the interval, I saw some lapis lazuli snuffboxes that were that same wonderful indigo, and I thought, "Good, the color exists in the external world." But in the second half I got restless, and when I saw the snuffboxes again, they were no longer indigo -- they were blue, mauve, pink. I've never seen that color since." (interview with Wired)
This anecdote pretty much sums it up. Looking for your favourite color among a number of color swatches is similar to Sacks looking for his mystical indigo. You'll never be able to find it in the 'real' world.