Tons upon tons of awesome funny lines. But if I'm going to single any line out, it has to Aang in the season finale of LoK: "It is when we are at our lowest point that we are open to the greatest change."
Now for a funny one. I'm not really a Mako x Korra fan, but I LOL'd at this rather adult exchange: "I'm with Asami!"
"Yeah, but when you're with her you're thinking of me, aren't you?"
I like where Mako needed more water for Korra and Asami is washing the dishes and she is like "You're a fire bender go boil it yourself!"
Aiiyah so sassy <3 lol
Although she has the right to be sassy at that moment.