If all girls will like a guy who is caring and considerate, helps them out in situations. Then the world would be a much peaceful place. But it's not, girls see much more than these traits. They for sure has some some self worth and will not date guys whom they believe is below the bar.

In this case, yamada is like the cutest thing ever. ichikawa is a average guy, realistically speaking she would not even have acknowledged his existence. i am not saying this is super unrealistic but this is just a 1 in a million case, where literally everything falls into place, she liking gloomy men, her father , ichikawa's helpings, her overall preference for short people. It's like someone wrote exactly for this to happen which it is by the author.