|I think you've got a point. I looked at my reading list, and I honestly can only think of one manga where a relationship/potential relationship would work in real life. All the other ones would simply not last or wouldn't happen in the first place.
In Chihayafuru, I can see Taichi and Chihaya actually working. They both share a common interest and are both smart, and unlike Arata he's willing to stay with her and work around her density. Not only that, but unlike Arata he's able to actually balance her passion for Karuta. I can't see Arata and Chiha working out because having two people so obsessed with something that they can't think of anything else wouldn't work out.
Does the walker choose the path, or the path the walker?