The biggest though has to be the ending to chapter 27. Minato has finally learned that Kushina is the 9 Tails Jinchuriki, and that she and many others have been lying to him about this for years. This eventually results in Minato being nearly killed by Kushina in 5 Tails mode. When Minato finally escaped from the hospital to confront her about this, he wasn't angry at her for that, but was instead angry that she never came to visit him in the hospital. He then tells her that he loves her, because she's "still Kushina, nothing's changed." Awww.
A small one was when Minato and Jiraiya were talking about Minato's Disappeared Dad, Minato declares that Jiraiya is his dad. Which is especially heartwarming when you recall that Jiraiya became a Parental Substitute for Minato's orphaned son, Naruto.