There were two in Control for me, both involving killer music: the ashtray maze and the altered movie camera. Absolutely grinning the entire time for both of those!
The first thing that comes to mind was my first play through of Yakuza 0. Majima spends so much time winning stuffed animals for a little girl that lost her dad. Part way through the quest line she starts calling him dad and it made him so happy. It warms the heart and I could not stop smiling.
Recently, Hi-Fi Rush made me smile (and laugh) more than once :)
Finally beating the asylum demon on my very first playthrough of dark souls.
Then i immediately realized i only just beat the tutorial.
Playing Dark Souls 1 for the first time has so many amazing moments like that - finally defeating the Bell Gargoyles, or surmounting Sens Fortress and pushing the Iron Golem off… But I don’t think anything will ever compare to the exhilaration I felt in beating Ornstein and Smough for the first time.