- How "Bad Po" treats Mr. Ping.
- Po's depression after his failure leads to everyone getting kicked out of the Jade Palace in "Sight For Sore Eyes".
- How the Furious Five reacted to Po messing up and getting them all kicked out was also able to swiftly bring tears about. And Tigress' tone when she blames Po...that's harsh.
- The Flashback to young Shifu training with Oogway, when he believed Oogway wanted nothing to do with him in favor of Po. Also, Po discovering that among the portraits in Shifu's room was one of him and Po. The guilt over this is one of the things that sends him to bring Shifu back from his 10-Minute Retirement.
Po: Master Shifu just can't accept that Oogway doesn't need him anymore!
- Prior to that, there's Shifu's almost childish excitement upon hearing that Po's met "Oogway's Ghost"... only for that to come crashing down in a tumble of hurt confusion when he hears his old master doesn't wish to see him. And his eventual challenging of Po and trading kernels of Oogway's wisdom that builds up to:
- And the lead-up to the Flashback, with Shifu trudging up to the peach blossom tree and speaking to Oogway, almost begging him to appear... Really, the whole episode is one tearjerker after another.
- "Owl Be Backk" (where Fengheung premieres) has Po learning that the strongest member would betray the team and everyone assuming he would eventually become evil. When he becomes consumed by worry, he heads off to the mountains to be isolated out of concern for his loved ones.
- The painful part is on how none of the 5 stop him when he announces he's leaving. Even when he goes to ask if anyone will, just the look of their faces show they are genuinely afraid he will grow evil and Po's despair that no one will stop him is heartbreaking.
- Tigress saying good-bye to Zan in "Kung Fu Daycare". Also the earlier moment when she tells him she'll never let him out of her sight again. And the flashback to her being left at Bao Gu by her parents, then playing checkers with Shifu.
- Tigress' reaction to Shifu's planned Heroic Sacrifice in "Enter The Dragon". The fact he's her adoptive father makes it even harder to watch.
- The whole episode "The Master and the Panda" is full of this. Peng not only discovers that his uncle Tai Lung was killed by Po, but also that his uncle was actually pure evil and had to be killed and gives up Kung Fu out of fear of being like him. It looks like it's getting better midway, with Peng coming back to help against an empowered Temutai, only for the power to possess him and drive him nuts, with only Po strong enough to stop him. He points out that Po won't always be around to do that, and leaves forever and swears off Kung Fu so he won't become a second Tai Lung.
- And Po trying so hard to reach out to Peng the whole time, even when he's angry as all get out or depressed.
- In "Present Tense", Sheng Xian's daughter reacting after Tigress' negative speech about the Winter Festival, about how she has little to no family, as Tigress reflects on how much she treasures Shifu and the Five as her own unofficial family.
- In "A Thousand and Twenty Questions" Master Yao reveals that one of the things Tigress really wants to know but is unwilling to ask is if Shifu is proud of her. Another is why she is always so angry all the time, which is likely related to the first.
- The reasons she didn't like the whole idea was because every time she asked a question when she was a kid, everyone at the orphanage would laugh at her because of how "stupid the question was".
- In "Crazy Little Ling called Love", we see how Po would react if or even when Shifu would retire. He was flat out devastated by it and was struggling not to tell the others as per Shifu's request.
- Also, just how tired Shifu seem to be. The fact that he shows regret and exhaustion over the life he has led is pretty painful. He simply wants to find happiness and he took Po's words from when Ling first appeared more seriously than any of us thought.
- "Serpent's Tooth" Holy crap. First we see Viper, the nicest, sweetest, friendliest member of the Furious Five being shunned by the fearful villagers for being snake because they're being terrorized by one. Although she brushes it off and tells Po it's okay, it's pretty clear she's hurt, especially when Po keeps making it worse through poorly thought out comments. Than we hear of Lord Fu-Xi, and how the once great hero lost has family thanks to prejudice at the hands of the people he fought to protect. Seeing how far Fu-Xi has fallen in his bitterness, Viper having to go off and fight someone she considers a hero, and her uncertainty in the face of his points even if she was acting seeing as Po isn't exactly proving him wrong. Finally Fu-Xi's shock when Viper reveals she was never on his side in the fist place. Heck, just seeing Viper lashing out and being unpleasant is pretty upsetting considering how sweet she normally is.
- "A Stitch in Time" starts off light and silly, with Po discovering a bag of seeds that turn back time and abusing their power for fun and profit. Then Fenghuang shows up.
- Shifu is killed by Fenghuang and dies in Po's arms.
"Po! You - you saved all of us!"
"Not all of us."
- Po uses the seeds to undo Shifu's death, only for Fenghuang to use the seed she took from him to erase his master from existence; and because Shifu never existed, the Furious Five never met, and one by one they vanish too.
- Po surrendering his life to Fenghuang in exchange for the promise that she fix the world, restore his friends, and set right what he made wrong. When he tells her it's only what he deserves, the regret and hopelessness in his voice is heartbreaking.
- Shifu is killed by Fenghuang and dies in Po's arms.
- Po The Croc has this with the Croc bandits realizing they turn po into a cruel monster as the episode progress.