This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / UFO Robo Grendizer
Daisuke remembering how Fleed was a beautiful planet but now it was a wasteland, and blaming himself for fleeing in spite of there was no alternative back then.
In episode 9, the Vegans sent a girl named Menao to assassinate Duke, promising that they would spare her planet if she succeeded. However she fell in love with Duke and she could not go through it. So SHE got killed by the Vegans, and she died in the arms of a distraught and helpless Duke.
For the evil forces, Minister Zuril watching his son die performig a Heroic Sacrifice.
The whole episode where Rubina appeared was a Tear Jerker from the beginning to the end. During the Rubina's death scene it was not only heart-breaking hearing her last words to Duke, but also watching Hikaru slipping away quietly to cry in silence. From that time, Duke and his friends knew there was no possibility of reaching a peaceful agreement with the enemy.
After the final battle, Daisuke and Maria telling goodbye to Hikaru and Kouji and Earth before returning to Fleed.