Something I don't see people mention much is a sense of dynamic resolution to mental imagery. I took the quiz posted here and it felt completely meaningless to me. If you want me to visualize a scene, there aren't really details until I give it details. If I'm told to imagine a wooden door with no other instructions it's like I'm seeing the door in a passing glance or out of the corner of my eye. If you ask me if it's "clear and vivid", I can make it that way to any arbitrary degree needed. Looking closer and seeing that the wood is old and somewhat warped, feel the cracks in the wood, look closer and see the brass on the handle has discolored slightly from use, etc etc. But it feels pointless to do. Certainly it's at least as detailed as a real life image, if I think about it, but it's definitely not like, crowding out my actual vision with it's sheer lucidity, which some of the answers seem to suggest.