I'll start. This is by no means a comprehensive list; just what immediately came to mind. When a character who features prominently during an episode disappears from the episode for no reason. For instance: in the TFA episode 'Thrill of the Hunt', Prowl, Bumblebee and Bulkhead are abruptly not seen or heard from ever again after they tangle with and get beaten by Lockdown. Only Optimus and Ratchet are seen back at the base at the episode's end. Rivalry between cops and federal agents. That shit is old, man. When every gun has over 9000 bullets. It isn't all too difficult to show reloading being performed. When a family's two children consist of a son who is a delinquent and a slacker, and a daughter who is smart and talented. Sexism works both ways. Kid characters who do not take their parents' or guardians' advice, wander off and get themselves into trouble. Carl from The Walking Dead... I hope the zombies take you next. Gratuitous nudity/sex scenes. You know, the ones that serve no purpose whatsoever and do not advance the plot in any way. When time travellers or interdimensional travellers are disbelieved and/or get institutionalized by people who think they're wacko. To be honest, this one doesn't annoy me as much as it upsets me. My heart really bleeds for characters like this: stranded in an unknown world and disregarded by everyone they meet.