If you're unfamiliar with the 2008 Dreamworks movie Kung Fu Panda, it is basically the world's most conventional believe-in-yourself, defy-convention, pursue-your-dreams movie. Po is a fat panda who dreams of becoming a kung fu master, and through a series of unlikely events, gets to do so. The movie beats on you and beats into you that self-confidence and willpower can overcome anything... that is, if you're the hero of the piece. If you're Tai Lung, you get to be utterly betrayed by every principle the movie espouses.
Quick background: Tai Lung is the adopted son of Master Shifu, who took him in and taught him kung fu. Tai Lung was a fantastically talented martial artist, and Shifu raised him and trained him to dream of becoming the Dragon Warrior, which one can only do by reading the Dragon Scroll. But Oogway, Shifu's master, told Tai Lung that he was unfit to read the Dragon Scroll, because there was darkness in his spirit. Enraged, Tai Lung went away and wreaked terror on the surrounding towns, until Oogway defeated and imprisoned him. Tai Lung comes back again in the movie to claim the Dragon Scroll, only to be defeated by Po.
Now (spoiler alert), there's nothing written on the Dragon Scroll. It's a mirror. You look in it and see yourself, that is, a reminder of the limitless potential that only you can achieve. Only one person knows that, however, until the scroll is revealed late in the movie. Even Shifu did not know what was inside the scroll, but it seems fair to assume that Oogway would have--he invented kung fu, after all, and he was the arbiter of whether people were ready to see what was inside. So when Oogway told Tai Lung that he was not worthy to look upon the scroll, he was knowingly saying that he was unworthy of the power of self-belief. He had no right to self-confidence. Oogway was telling Tai Lung, albeit indirectly, that his entire personality was irredeemably awful.
It gets worse. We learn in the movie that Shifu was chiefly responsible for Tai Lung's rampages. He was the one who trained him, after all, and he was the one who raised Shifu to dream of the Dragon Warrior's power. But it was exactly that desire for power that caused Oogway to reject Tai Lung. That was the darkness inside him that Oogway rejected. Between the two of them, these two kung fu masters--the elders he respected, the surrogate father he adored, the holder of all kung fu wisdom that Tai Lung must have idolized--raised Tai Lung to be ambitious and angry, and then cast him out and eventually imprisoned him because he had those emotions.
Now, Po is an entirely different sort of student from Tai Lung. He doesn't want to be the Dragon Warrior, just to be good at kung fu; he has little natural ability unless he's trained in a blazingly unconventional way, and by embracing his slapstick, ass-backwards, weirdo talent for the discipline, he is eventually deemed worthy of the power of self-belief. But before Po vanquishes Tai Lung, a returned Tai Lung beats up Shifu, screaming "All I ever did, I did to make you proud! Tell me how proud you are!". Shifu, who has been unable to achieve inner peace and who has been an emotionally stunted hermit for years because of his lingering guilt over Tai Lung's banishment, apologizes to him for the wrongs he's done, and Tai Lung snarls "I don't want your apology. I want my scroll". (Remember, Tai Lung thinks it's a gateway to limitless power, not a self-help book.) Po shows up, defeats Tai Lung, and the movie ends with Shifu achieving inner peace.
One would think that the only possible moment in the final Tai Lung-Shifu encounter (since most of it is spent beating each other up, or with Tai Lung speaking aloud every single thing Shifu's probably been torturing himself with over the years) from which Shifu could have achieved inner peace, is from Tai Lung rejecting Shifu when he tried to apologize. I think that in the mind of Shifu, this is when he can officially discharge responsibility for Tai Lung's crippled life. That's when he goes from wronged son to murderous tyrant, and when Po dispatches him, Shifu can be free. All that guilt and all that shame is just magically wiped out in one moment of catharsis. And when Tai Lung is defeated and banished, dead for all we know, Shifu can be at peace because that worry is out of his life. He doesn't feel sorry for his dead son, or guilty about the path he made him take, anymore. He's at peace.
Coda: Yes, Tai Lung is not an innocent victim in this story. He chooses to go on a rampage after being denied the scroll. He chooses to turn down the apology and beat up Shifu, and to go after Po even after the secret has been revealed. He is an actor that makes his own choices and decisions, but the entire reason for his villainy is because his teachers and his parent set him on a path towards it. That's the tragedy for me in this story.