I don't like this show. Why? It's boring. Because of that, I don't care and in a way, that's why everyone else loves it.
When I watched episode one of Clannad way back when, I was irritated. This was my second anime, and I was also watching my first anime, Naruto. I wanted to watch that instead. I was a testosterone-filled teenager who would rather see ninjas beating the crap out of each other instead of a slightly-older Japanese couple learning to cope with life. I got through it, but when it was time to watch its sequel, I was not amused. Because of my experience with the original, I could not become invested in After Story.
When the "tear-jerking" events in After Story happened, I just didn't care. I still don't. Since then, a certain anime called One Piece HAS made me cry, and that is much more than After Story did for me.
I hope you can see where I'm coming from. Its a personal thing, and that's the kind of story that After Story tried to be. Personal. It just didn't work for me.