Heartwarming / Field of Innocence

• Just everything with Lu Ten being Azula and Zuko's Big Brother Mentor: playing with them, teaching them how to bend, cheering them up when they're upset, and trying to guide them on the right path in life. He's such a sweetheart.
• Combined with Moment of Awesome, Lu Ten going berserk on Ozai when he finds out that he's been using training as an excuse to abuse his kids. Then afterward, he holds a scared five-year-old Azula in his arms and tries to comfort her:
  Lu Ten: It's all right now. Your dad won't do anything to hurt you again, I made sure of it.
• Lu Ten falling in love with Jun while in the Earth Kingdom. He offers to take her back to the Fire Nation to live with him when he's finished his duty there, and he's completely sincere about it. But of course, it won't work out...