- The live video phone call in the space rover, followed by a particularly wrenching shot of the Earth to remind the viewer just how far from home Sam is. "That's enough, that's enough... I want to go home..."
- To make it more tearjerking, there's also Clint Mansell's score during the scene. "Memories (Someone We'll Never Know)" perfectly captures the heart-shattering realization that Sam is too late to see his family.
- GERTY when he tells Sam he is a clone and sees his friend of three years breakdown in tears. "I'm very sorry." [robot arm pat] He even uses a crying emoticon.
- This is particularly tear-jerking when you realize that Sam is not looking at GERTY when GERTY shows the emoticon. GERTY isn't doing that for Sam's benefit; computer or not, he has enough emotions (or a good enough understanding of them) to truly feel sorry for Sam.
- Sam 1 willingly climbing back into the crashed rover to die and seeing Sam 2's escape capsule heading to Earth.
- The recordings of all the Sams before Sam 1. All of them happily believing they were going to see their family again, one of them even holding proudly his "family's" photograph. They probably believed they were really going home, right to the last minute, when they entered the mercy kill chamber. They're so pathetic in their doomed happiness it hurts.
- "How did Mommy die, sweetheart?"
- The Esoteric Happy Ending aspect: nobody in the story addresses the fact that even if Sam 2 exposes the corporation's horrible actions and ensures freedom for himself and the other Sam clones, they're all still doomed to live for only three years. One could argue they'll figure out how make the most of it, but it's still hard not to find the idea that you have to be content that you've got three mere years of life very tragic and saddening. Sam's clones are people with feelings, but their nature will sadly remind them that they will never be real human beings blessed with an entire lifetime of experiences and connections.
Tear Jerker / Moon