Tropes
When a character does something evil, cruel or very mean for no apparent gain, because the author wants to demonstrate that they are not a nice person and shift audience sympathy away from them.
What is Kick the Dog
A Power Trio of the "two Foils + balance" variety, this trope has three characters playing psychological positions.
What is a Freudian Trio
Take an otherwise uninteresting object, and have the other characters (or at least one character) interact with it as if it is a real.
What is a Companion Cube
This character type represents emotion and instinct, and desires gratification and pleasure.
What is the Id
A character who is set up to be thoroughly unbearable, with no wide range of anything (humor, relatability, competency, etc.).
What is a Hate Sink
This psychological character represents the rules and social conventions one lives by and desires perfection.
What is the Superego
When characters attempt to physically seal off access to a room, passageway or building, but are doomed to fail miserably due to poor choice of materials or bad tactical planning.
What is Absurdly Ineffective Barricade
This trope adds depth to a character by giving them some sort of psychological problem — always exactly one neatly-explainable and resolvable problem.
What is Epiphany Therapy
Car doors are designed to minimize weight and maximize protection against car crashes, and are thus mostly made from plastic with a thin metal plate on the outside; these materials do not, in fact, provide much protection against bullets.
What is Concealment Equals Cover