It is amazing how much people can mask, both from others and from themselves. One of my cousins is color blind (not sure which kind) and it wasn't diagnosed until he joined the navy as an electrician tech. He was utterly unable to read resistor color codes. I'm not sure how he made it that far in life without noticing; I'm guessing he implicitly was relying heavily on context cues (eg, the green stoplight is at the bottom).
Yeah I'm colorblind myself and usually it's not a big deal until I try to play a boardgame or tell good values from bad on random powerpoints at work. Every once in a while I'll pass a little regional airport with a "free flying lessons" sign and get excited before I remember that being colorblind precludes me from flying.
