Throw It In!: Many of Drake's one-liners were improvised, including:
"I will kick you to sleep!" in Uncharted 1.
"Aw, kitty got wet!" in Uncharted 2. It was originally thought of by Nolan North's son while playing Wii Tennis, which leads to it being one-upped with this random line during multiplayer. Referenced in Uncharted 3: "Aw, what's the matter? Kitty don't like getting wet?"
During a recording session for Uncharted 3, Nolan North watched a scene of Sully crossing a beam very wobbly, and immediately shouted "What are you, drunk?!"; to which Sully replied, "Maybe..."