Tear Jerker / Stargate Universe

• Future Rush accidentally killing Telford in "Twin Destinies". His reaction is just heartbreaking.
• The death of TJ's temporal duplicate from Lou Gehrig's disease in Epilogue
• The ending of "Gauntlet", made all the worse by the likely possibility that this is the last we'll ever see.
• Park being blinded, apparently permanently.
• Riley's death has a major impact, especially how he goes out. And everyone in the crew is hit pretty hard; his death gets mentioned in the next episode, to boot. Furthermore, due to being the one forced to Mercy Kill him, Young suffers a Heroic BSoD and develops a drinking problem that persists for several episodes, before he finally comes to term with what happened.
• The deaths of Ginn and Amanda Perry. And then again when Perry and Rush's selfishness necessitate Perry and Ginn's consciousnesses being locked away in different programming, denying them access to the crew any more.