When you have tritanomaly, blue often looks green.  You observe enough raised eyebrows and you lose confidence in your ability to tell the difference.  You begin consulting a non-afflicted expert when the difference matters, like picking out shoes to match your shirt.    But if you see blue and I see green, who is correct?  Well, since only one in 10,000 of us is a tritanope, correctness always resides with the majority – the non-afflicted.

Does it matter what we label colors?  I don’t think so, generally.  But on this one day of the year, if you are of Irish descent, getting it right matters.