"Why would I choose cosmic energy over Katara?" said Aang to the guru.

Meditating in the swamps of Degobah [1]

"I saw... I saw a city in the clouds."
"Mmm. Friends you have there."
"They were in pain."

[1] from wikipedia: The word Dagobah comes from a Sri Lankan term for a Buddhist stupa, or reliquary monument.