Dreams.

Interesting, but lonely. You can write long stories based on dreams ;)

Added 1 hour 12 minutes ago

The thing is, what you see isn't actually that hard to recreate if you replay it in your head after waking up. The problem is that dreams themselves lack detail; the brain doesn't work well in dreams and simply doesn't think about anything other than objects that are directly interesting to it.

When replaying the dream, the brain adds details that weren't actually there. When replaying it again, it might even be a completely "different" dream. It's a strange feature, just like how dreams are often quickly forgotten upon waking.

The brain itself overlays images on top of each other, like in a movie or slideshow.
A dream is already something incomplete.

Therefore, there's nothing wrong with us adding something of our own to the dream that wasn't actually there (if the brain hasn't already added it unintentionally). For example, you can take your own room and describe it "in reality," even though it only flashed by in your dream. This creates a kind of comparison between the dream and real life. As a result, we'll have details that were missing in the dream.