This depends much on mood, the season, temperature, etc. Oh, and the actual selection. Not to mention size of the steep. Variety in style, size, color seems to enhance the enjoyment for me.
Gyokuro is always smaller though. Cups are 1-2 or so ounces (30-60 ml) and somewhat upright in order to not lose any of the already low heat.
Material and texture are equally important ... the cup feel and weight.
While I may lean towards a lighter interior, it is not law as much as it used to be. Used to have to have a white interior, but then I discovered there were many ways to enhance the experience.