One of Kitaoka's first plans in the Rider War was to give Shinji a heroic BSOD by making him think he killed Zolda. This brings Shinji to the brink of suicide. But Ren helps him by exposing the ruse, despite the fact he says he doesn't care for Shinji. After Kitaoka calls Shinji a fool, Ren says: "He might be a fool, but he may be a better man than you and I."
Really, most scenes involving Shiro and Yui qualify for this but special mention has to go to Episode Final's ending credits. It begins with a young Yui playing alone on the swings until a young Shiro approaches from behind. He calls for her and then the two run to embrace each other.
This even gets more heartwarming when you consider that the swings imagery was also heavily used for young Yui in the movie.