Too true. Two otherwise sensible, college-educated friends of mine once insisted that they'd be able to tell how my eyesight is different if I sat down and drew what I see out of the window. Using pencil crayons that presumably pierced through my colourblindness. I literally could not find a way to explain to them why it made no sense.

"No, but we'll cover up the writing on the pencils so you can't read what colour they are"

EDIT: I realise I misrepresented the scenario. This wasn't talking about colour-blindness specifically, but in more of a "maybe the blue you see is my red" scenario.