Not being able to imagine anything means you cannot visualize a person's face, for example. You can recognize a person's face, but cannot picture it nor draw it. If you told me to imagine a mural filled of an ancient battlefield, only the verbal words would be regarded, but not any imagery.
Or imagine a fictional character with an golden armor set, average height, black hair, green eyes, in a battle stance. For me, I can only see the words, but not an image of this character. So it's essentially a written blueprint to me, but I can't make any sense out of what would incite fantasies from people. So I usually find books or novels seriously lacking in adequate description and leaving me wonder "how these events happen(ed), simultaneously?". So I don't like to read novels, but prefer comics where I am not forced to possess imagination.
The only time I might be able to sense something unreal is while dreaming - but it seems uncontrollable and more like watching a TV show - lucid dreams do not occur, ever. So maybe the subconscious might still be able to visualize, but it does so at its own whims. But even then, it's very limited and unclear of a vision, with no solid grasp of visual imagery. It's more like a series of slideshow than a solid movie. Perhaps dreams and imagination is actually unconnected..
The best I can do with imagination is being able to recall an existing picture/image - but this is very difficult and requires concentration (and closed eyes meanwhile) on that image, so it does not last long. I cannot transform or bring life to that standstill picture, as expected. It only works on characters/human beings, but only sometimes. A landscape, abstraction or a vision is impossible.
I can't think of unique names for stories, or even a synopsis or plot for one. I tried writing a few novels, but I lose interest and coherence after a few paragraphs. It just doesn't work out. I cannot plan out the plot ahead in advance either. I can never think of anything to draw, I can't make an original story for the life of me, and have lost the words for poetry as well.
I got asked recently about why not write a new poem, but I already have lost it all. I've written everything out from myself - I'm finished, done, complete. It looks like there is nothing left for me that requires a presence of an imagination. Maybe back as a child, I did have some imagination and could do great things with it - but since long years ago, that is a very distant history - feels like a millions lifetimes to me and now I'm just some void.
Seems the universe did pull a reverse on me and took away everything that provided the least bit of comfort for a solitary schizoid. I was surely not like this as a small kid. Now I can only consume other people's art, but it's like walking through the most majestic landscapes as a blind person, and can only sense/experience 10% of everything you encounter. It pales, but at least you learn to recognize and value that which others overlook. And frankly, only consuming a fragment of others' experiences bores me to hell.
Do I actually even exist if I have no 'me', can't express anything relating to 'me', possessing no story, and just going with the flow? Oh.
Now you may think that this is not much to toot a horn for, but then think again how visual-oriented human beings are. Learning becomes a much greater hurdle and you forget info much sooner too. The only way to learn is via repetition, until something imprints in the brain. That is all without any visual cues.
This also means zero emotional memories. Say, when I was at a trip in London, nothing could become exciting and I felt no need to take a single picture, even though the camera was there. Even if I'd browse old family photos it would be meaningless, because the 'me' there would be a different 'me' I could never relate to.
Perhaps the only good thing about this is not being able to relive any experience/memory in your head; which means, no traumas and no PTSD possible, ever. So even if you had the greatest day of your life or the worst, it all becomes meaningless the next day, disappears without a trace. So I could truly ask: "Why do I really live for like this?"
Next, imagine not being able to picture your lost family members. In which case, what meaning can they hold to you? That's right. They're gone and you don't miss them. They have dissolved from your life, and that's all. In fact, what meaning can you hold to your self? It all becomes empty and meaningless. Forget about other people if you have no substance to your self in the first place...
The other positive or good thing is that you can enjoy things for the first time again and again. You can listen to the same music over and over again and won't get bored of it. Still it won't get into your head no matter how many times you've listened to it. You can watch the same anime and won't remember the plot while rewatching the episodes and it'll be like a first experience ... but I don't do that, because I'm usually constantly bored and it's hard to concentrate and focus.
So it's no surprise I can't get angry or feel worked up (for longer than a few seconds anyway, if that) because I can't hold on to any emotional feeling and it instantly dissipates the moment it comes to existence.
When you can't imagine the future, you're always living in the moment. Yet the worst thing about living in the moment is that if the moment happens to be horrible, your entire existence becomes a living hell. You literally can't imagine ever feeling any other way. Getting rejected from a job means the beginning and an end to your experience, because you cannot imagine what comes next or what was before. I mean that literally. You have no past or future self to speak of, or take reference from. You can't take a journey back to a memory, or get comfort from music or anything - because the former does not exist and the latter has no effect on you.