why do we need sleep?

As I stumbled out of bed at noon for the 3rd consecutive day today and knock back another berocca in the vain assumption that they actually do anything, me brain starts a-wonderin' about sleep, and wtf we need it o_O

Can't we just take some pill that helps us create whatever it is that we create when we are asleep and then zombie out on the couch for a few hours to give our muscles a rest?

Anybody?

Because we haven't gone full cyborg yet and can run on batteries. It's coming though, don't worry.

It's healthier to just sleep, your mind and body need a break, and if said pills were created, you really think EVERYONE would sit and rest their bodies. No. People would abuse it and never rest, slowly and painfully killing them.
What are you, a retarded eight year old? Get a fucking life.

The brain needs to shut down, or at least change modes at night too. People that don't sleep for days on end apparently have memory loss since the brain organizes information at night.

Hah, I read that on the internet, that makes me smart.