Issue #16 of Stan Lee's original run, when Hank Pym, Janet van Dyne, and Tony Stark all decide to temporarily leave the team to get some rest from the constant exhaustion of fighting supervillains. When Captain America returns from a trip from South America, Hank immediately picks him up(in his giant form) and starts fooling around with Steve in a playful manner, leading Pietro and Wanda Maximoff, who are the new replacement members(along with Hawkeye), wishing that the X-Men or the Brotherhood of Mutants could have this kind of camaraderie. Also, Hank and Janet and Tony wishing one another farewell(they aren't aware of the other's identities at this point) and speaking fondly of the other as the issue ends. It's a very tender story overall.
The Vision is accepted into the Avengers after fighting against Ultron. He leaves in his usual stoic nature but only to show he is very human and begins crying in joy, shedding a single tear in a wonderful one-page panel.
A subtle one, but, Hank Pym and Tigra managing to find love for each other after the Skrull Invasion is defeated, a movement that begins when both determine they will be sensible over the fact Tigra's son William is, genetically, Hank's son as well, and culminates in the two of them rekindling a relationship that, so far, remains solid and sensible, and without any of the Unfortunate Implications that colored Hank's relationship with Janet Dyne. It's a subtle little side-story of two very broken individuals with long, traumatic pasts finally managing to heal a little and find love with each other.