Bill fer sure! His back and forth with Ellie is priceless.
So was when Joel said "Now Bill here is kind of strange. He has to get used to you, so you just hang back, stand still, and let me do all the talking". so what does Ellie do? She immediately starts beating him with a pipe! It was all the funnier because she couldn't possibly have hurt him.
And sassing him back: "Listen here, you little shit..." "Hey, FUCK you, man! You HANDCUFFED me!"
Those are the two best characters, and every single interaction between them was magnificent to watch!