> A pet peeve of mine is that "red on white" is considered bad while being, in fact, perfectly legible:

When I get my eyes tested at the opticians, one of the tests is usually looking at a red ring and a green ring against a white background and telling the optician which ring seems clearer. I think it's something to do with long/short sightedness? I'm shortsighted so the red ring is always clearer to me without glasses, and trying to read green writing on a whiteboard can be more difficult.