One common element is bad pacing. If an anime rushes through important plot points or drags on for too long in uninteresting parts, it can make you groan. For example, spending several episodes on a side - quest that has no real bearing on the overall story.
The 'free haru and reader groan story' is rather mysterious without further information. It could be that Haru is a unique character, perhaps with special abilities or a distinct personality. The 'reader' might be involved in Haru's journey or adventure, and the 'groan' could be a way to express various feelings such as frustration if things don't go as planned, or even excitement in unexpected situations. It could also be a story with elements of mystery, where the groan is a reaction to revelations along the way.
The main characters seem to be Haru and the reader. Haru is likely a named character with a role to play in the story, and the reader is also a key part as the story somehow involves them and elicits a 'groan' reaction from them.
Some anime with a lot of 'groan - worthy' storylines are those that have really forced romantic sub - plots. Like in an action - based anime, two characters who have no real chemistry are suddenly made to be in love just for the sake of having a love interest. It feels so out of place and makes you groan. Another case could be when an anime tries to be deep and philosophical but does it in such a clumsy way that it just comes off as pretentious.
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