A few things:
Humans already use 100% of their brains, just not efficiently. Immortality is impossible with the existence of entropy.
That is all.
Why don't you go kill some bunnies and kick some orphans while you're at it, dream-crusher. Oh yeah, don't forget to paint rainbows black.
Psst, can't paint rainbows. They're made of light.
Actually, they're made out of rain and bows. They're a UK-Africa joint project. UK supplies the rain, Africa supplies the bows. Then we hire Italians to paint them all nice colours and stuff. Greece donates the pot of gold at the end.
That's pretty funny, considering Greece is broke.