"Deliver Note" is an objective in the Story Mission Once and Future Slab in Borderlands 2
Head over to Brick. He will reach out with his hand. Just place the note in it as promoted. He will read it and then offer to take you out of the Buzzard Factory and head for Sanctuary.
As Brick is reading the note, look to the right of him. You will find a Sarcastic Slab. He will just walk toward and past you. But if you don't want his sass, you can kill him.