- Antony and Cleopatra. Who have even less excuse for this than Romeo and Juliet, seeing that they're not teenagers and that they are two of the most powerful people in the world. Antony ignores the advice of his generals to fight on land, and fights at sea because Cleopatra wants him to. Halfway through the battle, Cleopatra gets frightened and orders her ships to flee, and Antony orders his ships to FOLLOW HER. Naturally, he loses the battle, and blames Cleopatra. To test whether Antony still loves her, Cleopatra sends him a messenger bearing word that she is dead. When he hears this, Antony decides to kill himself, but he's almost too much of a coward to go through with it, and stabs himself in the wrong place so that he is badly wounded, but not yet dead. THEN Cleopatra sends another messenger to say "Oops, I was just messing with you!" What makes it worse is that this actually happened in Real Life. Antony and Cleopatra really were that dumb!
- So Hamlet just found out that his dad was killed by his uncle, but he still wants to spy around and make sure that the ghost was telling the truth. Fair enough. And then he decides to pretend to be insane, for absolutely no reason at all. There is no suspicion on him at this point and the uncle has no idea that the ghost even exists, let alone that it might warn Hamlet of what happened. Of course, his insane act is what gets everyone suspicious in the first place and sets up for the massive death scene at the end.
- Depending on the performance, Polonius could also count. Towards the middle of the play, he decides to hide in the queen's bedchamber to spy on her conversation with Hamlet. As things go on, he panics and starts screaming for help, leading a very paranoid Hamlet to run him through. If the actor playing Hamlet is sufficiently insane and frightening, it's a bit more understandable. Otherwise...
- In Pokémon: The Mew-sical, most of Team Rocket counts. Several Rocket Grunts annoy Giovanni and are shot as a result, and one Grunt reports that an agent fought a boulder for twenty minutes because they mistook it for a Graveler.
- The titular duo of Romeo and Juliet have known each other less than a few days, before they kill themselves in despair when they find each other's dead bodies. The play exacerbates this by making her wake up *the second* Romeo drinks the poison, before she stabs herself with his dagger.
- February, the schience officer from Starship who goes down to an uncharted alien planet and scans the air for breathability... after taking off her helmet. It gets worse from there.
- In Noah Smith's stage version of The Strange Case of Dr. Jekyll and Mr. Hyde, after hearing Jekyll confess to murder and that he can no longer control when he becomes Hyde, the characters let him leave the room to get his coat so they can take him to the police. Hyde returns seconds later with a gun.
- Sweeney Todd: The Demon Barber of Fleet Street: "Pirelli" recognizes a former employer, who so far as he knows is guilty of such a serious crime that he was transported to Australia. So, "Pirelli" decides to meet alone with this man, whose profession involves use of lethal weapons (straight razors), to try to blackmail him. Not exactly surprising that this piece of stupidity does end up being fatal.
- The Thousand Year Rose has Ciera, the witch. She has many moments of stupidity throughout the play, but moments before she and Wicked Witch Abigail are about to kill Kimmi, Kimmi says "quick, Ciera - let me go!" and Ciera drops her hold on Kimmi and cheerfully says "OK!"
- Westeros: An American Musical:
- Eddard Stark eventually figures out that his foster father did not die of a fever, but got killed because he had discovered a secret about the royal family and was about to expose it. Eddard's response to that is try to figure out what the secret was, plan to expose it himself and tell other people about his findings. Unsurprisingly, he doesn't last long.
- Robb Stark takes after his father. He promises Walder Frey an Arranged Marriage with one of his daughters in exchange for troops and the right to cross a bridge guarded by the Frey family. A few months later, he sleeps with another woman and makes up for it with a Honorable Marriage Proposal. The Freys retaliate by having Robb and his mother killed.
Too Dumb To Live / Theatre