This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / The Girl From Whirlpool
Tear Jerker: The ending of Chapter 24. Minato goes to cheer up Sakumo after his failed mission, only find his dead body and a traumatized Kakashi. Even though anyome who read Kakashi Gaiden knew it was coming, it was still tragic nonetheless.
Minato realizing that his girlfriend has been lying to him for years about who she is, while everyone else in her life knew that she had the 9 Tails within her. However, it does lead to an amazing Crowning Moment of Heartwarming.