If Science Is So Advanced Why Can't It Explain These Mysteries?

Just Why Do We Need Sleep Anyways?

Everyone knows they feel better after a good night's sleep, but as it turns out, scientists still don't know exactly why that is. There are some theories involving brain function and allowing for the process of daily memories and stimuli. These are backed by studies involving long-term sleep deprivation and mental illness, but still, the exact reason why evades modern scientists.