Whew, this is a tough question. I originally thought about choosing Little Busters!, but then I started remembering the first time I saw Clannad.
I thought about which one had the most effect on me, as a person. While I’d say Clannad was not the most emotional story I’ve experienced, it definitely had a drastic impact on me, specifically how I see my father.
I lost my father when I was about 12. I won’t go into too much detail, but for a few reasons, I was going through the entire grieving process again years later. I was trying to convince myself he was a horrible father, and that I didn’t care that he was gone. Of course, this was idiotic, but people do stupid things when they’re like that.
It was at this time that my friend introduced me to Clannad, and Key in general.
As soon as it started focusing on Tomoya’s relationship with his father, Naoyuki, in After Story, I realized my Dad wasn’t dissimilar to him, and neither was how we treated each other, basically strangers. Clannad (as cheesy as this sounds) really slapped me in the face as to how stupid I was being at the time. I obviously miss my father very much. He wasn’t a bad father, either. Nor do I hate him anymore.
Of course, Clannad didn’t completely change how I thought of him, but it was definitely the starting point for that change. For that, I’d have to say this spot belongs to Clannad, in my eyes.
I might’ve strayed from the question just a bit, if that’s the case, I apologize.