This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Mars Attacks!
Towards the end, when the Martian abductees crash into the ocean.
During the first attack all Jason Stone was thinking of was trying to get to Natalie. He was reduced to a skeleton before he could even hold her hand.
Billy-Glen's horrific death, and his parents' reactions to seeing it live on television. You feel bad for them even though they were all jerkasses.
Billy-Glen's Dad: [flipping through the channels hurriedly] ...no, that didn't happen to him... no, that didn't happen to him...
The Death of a Dog card in the original series is one for animal lovers. Many of the others in the series will wring tears even as they arouse horror.
Also, Byron's Almighty Mom and Plucky Girl of a wife's Cry Cute moment when she senses during the invasion that Byron might be dead. Right after he's shown all beaten up on the ground, the scene shows her tearing up and cradling their kids:
"Something happened... something happened to Byron