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Tear Jerker: TRON: Legacy
Sam and Kevin's awkward reunion can hit home for parents who are out of touch with their kids, or vice versa.
Sam: Long time.
It's brief but, Kevin's understandable reaction upon realizing who it really is that's chasing them
Kevin: Tron, what have you become?
"I fight for the Users."
The flashback where Kevin Flynn sees the genocide of the ISO programs and realizes that there's nothing he could do to stop it.
Then we get another flashback the explains what happened to Tron.
In Fridge terms, the scene where Kevin reveals to his son that Quorra is the last ISO and all of Kevin's efforts to disguise her as a regular program. The scene when she tells Sam how she escaped the genocide only makes it worse.