The one and only time I've shed a tear is when I had some time to kill, so sat down with my kids and turned on the telly and Fox and the Hound was on. And the end my daughter was crying inconsolably saying "They only wanted to be friends". That touched me way more than the movie ever could.
To be honest any line from the world's most passive aggressive AI could take this. GlaDOS is such a fantastically angry sinister presence. My favourite line (in which they cleverly set up her motivations for the sequel) has to be the line where she reveals that when she was 'killed' she actually got stuck in a memory loop that has been replaying the last 2 minutes of her life (and subsequently her violent death) for the past several years, so naturally not only has this has sent her mad, she directs that at Chell. Someday I wish I could write a character half as good as this.