Dreaming
Everyone dreams. Not everyone holds onto the memory of it. If you asked the person I share a bed with, he'd tell you flatly that he doesn't dream, or that whatever happens at night vanishes before morning. And yet I've woken up to find him halfway through some private drama, muttering lines out loud to nobody. For those who do keep their dreams, the usual advice is to write everything down the second your eyes open, before it slips. Plenty of guides exist that catalog dream symbols and what they supposedly mean. The catch is that a symbol rarely lands the same way for two different people.
There seems to be a purpose behind dreaming, or we wouldn't do it. The hours we spend asleep and dreaming seem to matter in some way we don't fully understand. Animals look like they dream too; ask almost any dog or cat owner and they'll describe the twitching paws, the muffled barks. Even very small children dream.
Some people describe their dreams as actual travel, as though they've left the body behind for a while. The sensation of flying or floating in a dream gets pointed to as evidence for that. They talk about visiting places, and meeting people who have died or whom they simply haven't crossed paths with in years. Whether or not any of that happens, the faces do show up in the dream, and the dreamer remembers them being there.
Nightmares are close to universal. Most of us know the kind: something is after you, you're running, and the escape never quite works. Now and then the fear comes with a paralysis that feels total in the moment. You know you can't move, you know you want to wake up and can't, and you're stuck there aware of the whole thing.
And then there's lucid dreaming, where part of you stays awake to the fact that none of it is real. People who do this say they can keep that awareness going and steer the dream wherever they want it to go.