Dreams

Life is a series of days, filled with hours. And in those hours are minutes and then seconds and milliseconds, and it just keeps going.
You have choice, which makes this time seem to go faster. The red one, or the blue one? Water, or something less healthy but better tasting? You don't always think you have choices? Think again. Even with huge things like the presidency, you can still choose who you vote for.
I can bet I can tell you something you can't choose.
(And no, it's not family. You can run away, and there are many ways away from them.)
It's dreams.
No matter how hard you think about something, or if you fall asleep looking at something, you can't control what happens in those dreams.
Where you aware that every night, you dream? You know that feeling you have when you know you dreamed but can't remember what you dreamed? Well, what if your dream ended before you woke up? You can't always remember every dream, but they're there, every night.
Dreaming was made because sleeping is the closest thing to death without death.
If you just slept, every night, you would experience death and what death feels like without dying. Sort of like immortality, right? Well, we can't have that. Dreams are to replace death before death.