Intriguing question! I guess we do see dreams, when we think of an image. Perhaps these images are so vivid when we sleep because the rest of our bodies are active, and our imagination has more of an effect over our bodies, but I’m really not sure.
Good question pnug!
We have dream because when we sleep our brain has to sort out all of our thoughts and ideas and memories. As our brain does this we see some of them all scrambled together which is why dreams can be so weird! We don’t have dreams when we are awake because out brain is busy doing all the other stuff that we need it to do whilst we are moving around, thinking and talking.
This is why sleep is so important as its our brains chance to sort everything and be ready for the next day.