A lot of people missed the bigger picture in this fight scene. This fight scene shows the huge difference between Korra and Aang. I remember in the beginning of the Legend of Korra when Korra was sparing with some white Lotus guards, she went head to head with all 4 of them but the general said something while he watch her fight. Katara was amazed by how skillful korra has become. She said; "She's strong" The white lotus general said; "She lacks restraint". Truly, Korra Lacks restraint. I could give you several of instances from the series. Though she's a water bending Prodigy and a prolific skillful fighter but she doesn't know when to say "Enough!!" She wants to do everything in her power to win so she could prove something. She did this against The Equalist and Amon, Zaheer and Kuvira. Now in this clip, Aang spared with korra and still know when to hold back. But korra went Bizarre cos she wants to win by all means. When Aang saw that she was without restraint, he stopped fighting so that Korra could stop, then he sadly walked away cos he was only sparing with her but she took the fight too personal. Yes Korra is strong, but there is a difference in being in control while fighting and opponent, and losing yourself in the fight that you become a Monster. Maybe this was why In the Legend of Pavi, the claimed Korra caused the catalyst then all benders fought against her then they saw Avatars as an enemy not as the Hero/Saviour. Thanks for reading my two cents.