I always wondered whether a good way to describe Aphantasia to people who don't have it is to ask them to "imagine" an odor. Most people can recognize specific oders effortlessly and remember them for decades (example: you smell some brand of aftershave, and you immediately know that this is how your great-grandfather always smelled, who has been dead for 20 years), but you cannot "think" of an odor and actually smell it the same way you can think of an apple and see and inspect its image inside your head. Yet you "know" what gasoline smells like, or fresh bread.

This leads to another interesting question: are there people who cannot imagine music and other sounds, like speech? Is this related to Aphantasia?

A question even more interesting: are there people who can imagine odors, or combinations of them? I would expect this to be very handy if you are designing perfume, for example.