This is based on opinion. Please don't list it on a work's trope example list.
Tearjerker / A Nightmare on Elm Street 3: Dream Warriors
The death of Nancy Thompson. Kristen's whining scenes may seem a little Narmy, but when she promises to dream Nancy into a "beautiful dream", it brings the waterworks. Even worse, what did her in was her desire to finally make peace with her estranged father, which Freddy used as a cruel trick.
Big, snarky tough guy Kincaid spends his night in the Panic Room curled up in a corner, singing the same doggerel rhyme to himself over and over to keep awake. For all his macho, stoic posing in front of the others, the poor kid is still only a scared teen in a dark place, alone.