Sometimes, a trope isn't the tree. It's the whole forest.
That is, when you see something used in fiction, it can seem to not mean anything. It's an artistic choice on the part of the creator, but it has no actual meaning beyond that and you might be tempted to label it "not a trope."
Until you look at a whole genre, or even all of fiction, and notice that this particular artistic choice happens a lot. A lot more than it ever happens in Real Life, in fact. It's nearly universal to a genre.
What you have here is an Aggregate Trope. It's a storytelling pattern, but that pattern only becomes apparent when you take all the examples as a whole rather than look at individual examples. The key word here, is "tendency".
Compare Garnishing the Story (in that the pattern is completed by the notion that the elements improve a story by their inclusion).
Many of these are examples of Tropes Hidden from Audience, as the audience only "notices" them after they appear within a number of works.
Tropes that are only a trope in aggregate:
- Acceptable Feminine Goals and Traits
- Adults Are Useless
- All Abusers Are Male
- All Gays Are Pedophiles
- All Men Are Perverts
- All Women Are Lustful
- All Women Are Prudes
- Always Identical Twins
- Asian Store-Owner
- Asimov's Three Kinds of Science Fiction: Sci Fi inventions can be the focus of the story, a prop, or a societal impact.
- Bald Head of Toughness
- Bald of Authority
- Black Dude Dies First
- Blue Is Heroic
- Bury Your Gays
- But Not Too Bi
- But Not Too Evil
- But Not Too Foreign
- But Not Too Gay
- But Not Too White
- Cast Full of Gay
- Double Standard: Abuse, Female on Male
- Everybody Is Single
- Everyone Is Bi
- Fandom-Specific Plot
- Female Rockers Play Bass
- Five-Man Band
- Geek Reference Pool
- Girl on Girl Is Hot (when paired with hate for Guy on Guy Is Hot) note
- Girls Are Really Scared of Horror Movies
- Heroes Prefer Swords
- Heroic Build
- Hollywood Beauty Standards
- I'm a Man; I Can't Help It
- Improbable Infant Survival
- Men Are Generic, Women Are Special
- Men Are Tough
- Men Get Old, Women Get Replaced
- Most Common Superpower
- My Girl Is Not a Slut
- Never a Self-Made Woman
- No Bisexuals
- Nothing but Hits
- Obvious Crossover Method
- Quantity vs. Quality
- Real Men Hate Affection
- Real Women Don't Wear Dresses
- Small Reference Pools
- Small Taxonomy Pools
- The Smurfette Principle
- Sour Prudes
- Stock Food Depictions
- There Are No Therapists
- Token Lesbian
- Transgender Fetishization
- Unto Us a Son and Daughter Are Born
- Vanity Is Feminine
- Vasquez Always Dies
- Villains Act, Heroes React
- Wet Blanket Wife
- Women Are Delicate
- World of No Grandparents