Oliver is terrible about birthdays, and especially about giving gifts. His first idea didn't work out, but he figures he can simply tell Tris about it, rather than try to navigate the minefield of gift giving. (He'd seen a nice necklace in passing once, but the idea of giving a necklace to someone other than Thea or Felicity felt strange.)

He leaves his and Felicity's birthday card to Tris on the table collecting such things, and grabs a drink before heading over to the birthday girl.

"Happy birthday," he says as he approaches, smile on his face.