Reading some negative reviews of that anime about the people grieving over their friend's death, I mentioned last page. The reviews were written by people so immersed in fiction that they don't know what reality looks like.
The reviewer's complaint was that in-between being unhappy/grieving, the characters were occasionally normal, or even happy, before becoming sad again. Apparently this was "unrealistic". Also, he didn't like how there was no actual plot-point of them "getting over it", rather, they just gradually were upset less often until they pretty much forgot about it. He saw this as a plot hole. so this guy thinks the realistic way to depict grief is someone who's sad
constantly until some well-defined life-changing moment happens then they're magically happy after that. Viewer reviewers suck*.
* Or, I should say that people who spend all their time writing anime reviews about how they don't think the human interactions are realistic don't actually seem very knowledgeable about how real humans behave
a common thing from these guys is to claim that people freaking out under pressure or making errors of judgement in a series is "unrealistic", because apparently they should all be John Mcclane under pressure. The logical thing to do would be to pick up the pitchfork and skewer the zombie, so that's how every character should act in such a scene, for "realism". That's how this logic goes.