My favourite brown shirt is green. Normally, I don't like brown, but I like that one. I wore it for years thinking it was brown until I said something to my wife that made her look at me funny (ier than usual).

My colour confusion is particular: Certain pinks and purples are grey, certain colours aren't quite right (like my "brown" shirt), and I cannot see red unless it is "bright enough". I see the red of an apple just fine, but Mars has always been a faint object of uncertain colour. I always thought people were waxing poetic until I learned of my colour confusion.

I really do prefer that term, by the way, not for any reasons of political correctness, but because it is far more accurate, and gets people inquiring as to just what I mean. If I say "colour blind", they assume red-green - I have no problems with red or green or Red Green, and see traffic lights the way FSM made 'em.

The only time my colour perception has caused me problems at a computer is when someone insists on pink fonts on grey backgrounds. It's not just that it's hard to read, it hurts. It really, really hurts to look.

For me, there is minimal contrast and no edge definition, so the letters float and shift on the screen and it is painful to look at. Highlight the text, flip the contrast, readability restored.