-Technical innacuracies, such as drawing details on firearms or vehicles wrong, referring to things with incorrect terminology, etc
-Stupid explanations. Some of the worst offenders are trendy subjects that not many people know enough about to portray accurately, like nuclear science or time travel.
-Unlikable, un-self-insertable, pieces of shit in romance anime. I don't know about japs, but I don't see myself as this insufferable, especially not in this way.
-"Hollywood physics", IE, chloroform = perfect knockout drug, no brain damage from trauma to head, etc