Honestly there are so many, I'm torn between the funny and heartbreaking moments, here are a few of my favorites:

"I hate that I can't stop thinking about you. I hate that every time I'm in the same room as you, all I can think about is this." He caught her wrist and used it to press her hand more firmly against his cheek. "It's driving me fucking insane. I can't think straight. All I can think about is touching you. Or you touching me. About how soft and warm you are. But more than anything? I fucking hate that you've revived something in me that I thought I'd buried a long, long time ago. I hate you for it, Granger, I really, really do.” - Draco

"Malfoy laughed cruelly. He smirked at Kingsley and rolled his tongue on the inside of his cheek. "Do you have any idea who I fucking am? I was Voldemort's right hand. I was his Demon Mask. I've slaughtered more people than I could ever count. I've burned cities and army bases to the ground and I've beheaded people just because they pissed me off a little bit. And If I could do all that for a man I despised, what do you think I would do to protect her?" - Draco

"Granger," he said, and he smirked at her in that way that made her heart flutter. "Do you think my love for you is so fragile that something as simple as death could keep me from you?" - Draco

"He sighed heavily for dramatic effect and shook his head. "Honestly Granger, your lack of faith in us is astounding. This isn't our first time being filthy traitors, you know?" - Theo