The Love Rhombus
Every great adventure has romance, and over time Lost expanded from the original love triangle between Jack, Kate, and Sawyer to reveal that tortured romances were as much a part of the show's backbone as daddy issues. But the main love strife that had been there from the beginning soon became unbearable as it morphed into young adult melodrama.
The high school fuckery started with a randy, death fearing Sawyer and Kate copulating in cages while Ben and Jack watched, and got more complex when Juliet entered the fray and configured it into a bizarre rhombus full of jealous glances, awkward exchanges, consolation kisses, and revenge tent sex.
The nonsense crescendos in season five, when Jack, still smarting from his failed engagement to Kate, resolves to detonate a nuclear bomb with the hopes that it will alter time so they never met, and the usually level-headed Juliet agrees to help him because pseudo-husband Sawyer keeps flashing puppy dog eyes at Kate and falling back on affectionate nicknames. Face, meet palm.