1. Bodyswapping
BBC WorldwideWhile it may not be as overused as some of the other entries on this list, there are few plots more obnoxious than the bodyswap sometimes known as the Freaky Friday plot, named after the movie where a mother and daughter switch bodies by wishing really hard. If youre unfortunate enough to be watching a bodyswap episode, the best you can hope for is that itll be played for laughs the actors will have a good time mimicking one another and therell be a bunch of in-jokes and sight gags as characters attempt to control unfamiliar superpowers or body parts. Even the stoniest heart cant resist the simple charm of Red Dwarfs Rimmer, at his first meal in three million years, pouring gravy over his own head. Its when the bodyswap is used to inject peril or drama that everything collapses for instance, when the villain takes over the heros body and the hero finds themselves trapped in an asylum or surrounded by thugs and murderers, escaping just in time for the inevitable fighting yourself battle at the episodes climax. If your best friend suddenly forgot where they lived, every shared adventure and the fact that they have a lethal peanut allergy well, you might not immediately deduce the truth, but nor would you shrug it off as them not feeling well. These are characters who deal with alien possession, intelligent viruses and energy beings on a daily basis - but in spite of all their prior experience, everyone has to lose 50 IQ points for this plot to work. If you have to make your characters uncharacteristically stupid to tell a story, it probably isnt a story worth telling.