Vibrant colors dont necessarily mean enjoyment. As you can see when a male sees another male, he will fire up. That is not a sign of enjoyment. Mellow colors, at least for my veileds, are of a brownish hue. These are the colors I find them in while they are undisturbed by any outside influence, such as myself. Any alteration in their comfort zone, such as me coming close, they will lighten up.
These are just my observations on my chameleons only.