Oftentimes, when someone wants to express extreme gratitude or well-wishing, they say "May all your dreams come true." I find this very strange and counter-intuitive, as I can hardly think of a more unpleasant thing to wish on someone.
Think about it. What kind of dreams do you have, if you can remember them? Do they tend to be idyllic romps through tropical paradises? Probably not. Most people have dreams about what they encounter in everyday life: friends, family, school, and work. Visions of your old house or school are far more common than a nighttime visit to the Big Rock Candy Mountains.
Researchers from the University of California, Santa Cruz, divide dream-emotions into five broad categories: Anger, Apprehension Sadness, Confusion, and Happiness. Notice that positive emotions take up only one-fifth of the spaces on the list. Seems to me that joy and contentment are less common in dreams than many people believe, despite extensive experience to the contrary in their own dream-lives.
However, just because "Happiness" is the only positive emotion on the list doesn't mean it's the least-commonly experienced. If it weren't a common emotion, it wouldn't be on the list at all. I'm just saying that other emotions are important, too, and we need dreams in order to explore them. If your brain just replayed positive memories and fantasies all night long, what good would that do? If you wanted placid, inoffensive nightly entertainment, you could just as well watch Lifetime. Dreams dealing with the other emotions are more important than the happy ones, because they allow us tho confront our dilemmas (even ones we're not consciously aware of) in new and creative ways.
If you go to an online dream database and read a few dream summaries, it quickly becomes clear that very few of them are about "happy" subjects. They often include bizarre and frightening imagery, the significance of which is sometimes only known the the dreamers themselves.
Admittedly, positive dreams may be reported less often because they are less memorable, seen as less important, or may express desires the dreamer does not feel comfortable sharing with the rest of the world.
But even so, whatever kind of dreams a person may experience, a wish that they all may come true is clearly a disastrous wish for one simple reason: nightmares.
As anyone who has had a nightmare can tell you, they're not fun. And almost everyone has had one at some point in their lives. So why would anyone wish for all of someone's dreams to come true, if they know that they've probably had at least one nightmare in the past? The only thing about nightmares that makes them bearable is the fact that they end! And when you wake up, they (hopefully) will have no bearing on the rest of your life.
So, with all this in mind, why on Earth would anyone ever wish for ALL of someone's dreams to come true?!