In hindsight, their music video for "It's You" can become this. Not only is it more melancholy and nostalgic in tone compared to how their promo singles typically are, it's also the last music video where Kibum and Han Geng appear.
For the same two reasons, Super Junior M's "Blue Tomorrow" is also a Tearjerker.
Explorers of the Human Body
Eunhyuk admitting he would be destroyed if the group got to disband. Counts as Harsher in Hindsight when we took events of late 2011, thought.
Although it was for the show's goal (get Ryeowook and Eunhyuk's tears), Kyuhyun's declaration of him feeling insecure about his health condition and failing to be useful to the group is very heartbreaking, especially if you consider all of this is true.
