The problem with Ano Hana: The Flower That Geneijin Saw That Day is that it's a bad melodrama. By that I mean, as is common with bad melodrama, it seeks to move the viewer, not through quality characterization and tragedy that speaks to the human condition in weighty manner, but through cheap, unearned sentimentality and contrived, throwaway drama.
This is something hardly exclusive to Ano Hana as far as anime goes(see certain other series written by Jun Maeda or Mari Okada), but it's especially noticeable in this case because of how especially weak and capricious the writing is. Storylines are brought up and then dropped abruptly, like Anaru's bad behavior fueled by peer pressure. The show spends multiple episodes on an arc about building a rocket that is ultimately meaningless. The characters don't think to try obvious things like Menma writing in a notebook until the show is almost over. The characters either have nonexistent characterization(Tsuruko), or the characterization they do have is cliched and stupid(Anaru, Yukiatsu). What pathos exists in the show is trivialized by a meaningless love quadrangle that goes nowhere.
Ano Hana is a show which had lots of potential which was squandered with one of the poorest possible scripts.
I can't be too harsh on it as we exist in a world where Angel Beats is lauded.