Between the Saki manga and this one, I gotta say the author writes some risque stuff, but they're very competent at doing so. There's more to this story than the landmine that is trying to navigate around a minor's romantic curiosity.
Read probably a hundred or more manga, and I can only think of a handful that really show you the nitty gritty of an unfulfilled work-life, and near-traumatic experience that comes with working for a shitty employer or supervisor. Fumi takes it, but you see how it chips away at him. It's really not uncommon in life for someone to either put up with it, report it, or leave.