There is, apparently, an association in the UK between green ink and rambling letters to the editor about fluoridation, Reticulan hybrid babies and surplus Soviet mind-control laser satellites. With some greens, this is a perfectly understandable association, even if the UK also sees a link between green ink and the head of MI5… well, actually, maybe there is a causal link there, too. In any event, while some greens are a little wild, others are so mellow that any connection between them and raving lunacy seems impossible.
I have thus arranged the tones in a more subjective way than some of the other colours, along my estimate of the relative sanity of the sort of person who would use that colour. You may judge the utility of this arrangement in light of the fact that I rather like green ink.