Is it difficult for you adults to use your imagination, fantasize?

What the hell do you think authors like Shakespeare, Milton, Tolkien, G.R.R. Martin, etc., were using, if it wasn't their imagination? A Magic Eight-Ball, maybe?

No, that's not difficult at all.

I agree with Speed. I also think your challenge is too general as well as insulting. "You adults". Huh! We adults can imagine stories that don't  need fairies, superheroes, magic, monsters, supernatural creatures, ghouls and chainsaw wielding killers.  If we want them, we can make them up as well as any 12 to 20 year old. Most old geezers can describe their actions better. We are not stuck on names and appearance or on what "superpowers" our characters must have. What is the point of wizards when the muggles live, love, and get into and out of trouble without magic?  "Harry Potter" is a good read, but so are "Gone With the Wind", "Azincourt", Colleen McCullough's books about Sulla and Caesar, "The Adventures of Huckleberry Finn", "Operation Mincemeat" and any book about the sinking of the Titanic,  IMO. No magical creatures or superpowers, but I can imagine what I read, and frankly a book about the Titanic or a casualty clearing station in World War I is more horrible than "Dracula" to me.

No, we simply can't do it. Not one of the people here daydreams, imagines situations which are not real, or writes fiction. We become incapable as the clock strikes midnight on the twenty-first birthday.

Seriously, Artour, that's fairly insulting to even ask. Of course we can use our imaginations and spin fantasies. Because we are more widely read and have substantially more life experience, we can probably do it better than younger people.

I have an incredible imagination. It's one of my strengths.