The Last Airbenders

The techniques used by Long Feng to brainwash Jet and Judy(s) and many others are actually quite feasible.

Long Feng is seen using a technique called NLP Anchoring.

From the wikipedia (http://en.wikipedia.org/wiki/Anchoring_%28NLP%29)

Anchoring is a neuro-linguistic programming (NLP) term for the process by which memory recall, state change or other responses become associated with (anchored to) some stimulus, in such a way that perception of the stimulus (the anchor) leads by reflex to the anchored response occurring. The stimulus may be quite neutral or even out of conscious awareness, and the response may be either positive or negative. They are capable of being formed and reinforced by repeated stimuli, …

Skeptical? Do a search below for “Derren Brown”, watch some youtube clips, and see for your self.