You’re painting with the wrong colour
You were taught that primary colours are those that can’t be made by mixing other coloured pigments together, and that all other colours can by produced by blending these primary colours. Red and blue fail on both counts. You can make red by mixing yellow with magenta. While a blend of magenta with cyan yields blue. Meanwhile a massive range of hues are inaccessible if you start with just red, blue and yellow.
Colour theorists had this all worked out by the end of the 19th century but for some reason it hasn’t made it to school curriculums. The proof is in your colour printer cartridges. They come in cyan, yellow and magenta, which are the true primary colours.
A bitter taste in your mouth
Remember those tongue maps that crop up in biology text books? They clearly show how the taste buds for bitter sit at the back of the tongue, with sweet, sour and sweet having their own discrete regions.
These tongue maps first appeared in 1942 after Edwin Boring of Harvard University misinterpreted a German study from 1901. Despite Boring’s mistake the maps soon started to appear in schools texts. Then in 1974 the topic was revisited and the whole idea was roundly discredited. Nevertheless over 40 years later tongue taste maps still persist in biology text books.