Tropes that are there because the writer had to include them - especially when a sharp-eyed viewer can tell the creator would have preferred to leave them out.
It happens for a number of reasons:
- Systematic Executive Meddling
- Moral Guardians
- A Censorship Bureau
- Necessary Weasel (Requirements of the genre. For instance, if you want to do a Police Procedural, you had better include the procedure.)
- Constraints of the medium
- Government regulations
- 555: Fictional phone numbers and addresses may need to avoid corresponding to ones in Real Life.
- The Audible Sharpness in The Lord of the Rings was going to be averted, until test audiences had trouble accepting the absence of the trope.
- Avoid the Dreaded G Rating. It's presumed that any work that can be seen without moral qualms by anyone, regardless of age, is not worth seeing by adults ("children will watch anything"). Since this would cut into profits by scaring off parts of the potential audience, it needs to be avoided.
- Being forced to Bowdlerise a work. The enforcers could be Moral Guardians, government requirements, or Executive Meddling.
- Censorship Tropes. You can't ignore the censors without consequences.
- The Coconut Effect, because Reality Is Unrealistic.
- Coconut Superpowers, because of budgetary problems during production.
- Dawson Casting can sometimes be necessary for legal reasons. One example is the film adaptation of The Reader. Michael Kross legally couldn't shoot his sex scenes with Kate Winslet until he had turned 18.
- Did Not Do the Research: Any medium that relies on a small amount of people on a hectic time table will occasionally not be able to do the research correctly, and make some mistakes. Especially if they're on a contract.
- Merchandise-Driven: Any work that exists to promote or sell a product (such as a line of toys) will be constrained by product availability, turnover, popularity and gimmicks. Transformers is probably the most successful example.
- No Budget: When the creators are limited by budget constraints.
- Our Lawyers Advised This Trope: Legal disclaimers are necessary to stave off attacks from overzealous lawyers.
- Pac-Man Fever. Using a modern game would involve licensing or Product Placement agreements. Generic 80s arcade sounds do not.
- Rated "M" for Money is often caused by Executive Meddling.
- When fiction deals with the history of some region, it may sometimes need Rose-Tinted Narrative to get mainstream success in that region. In worse cases, Rose-Tinted Narrative will be required for publication.
- The Deep South in the first several decades of film got a lot of rose-tinting.
- Also happens with other works that require the authorization of their subjects - authorized biographies, for instance.
- A Spiritual Successor may be created because a legal dispute renders a true sequel impossible.
- White Male Lead is usually employed because the entertainment industry knows that any female or non-white lead will be called racist or sexist for the portrayal no matter what they do, prohibiting character flaws required to make an interesting character.
- Your Princess Is in Another Castle is all but unavoidable in TV series if they run long enough.