Across the web, I see people converting Popular Science Fiction Movie, Popular Fantasy TV Show, or Popular Videogame into their favorite tabletop RPG. I have always had a difficult time playing in other people's sandboxes, especially when those sandboxes weren't made with tabletop RPGs in mind.
I know this is a common part of tabletop RPG culture. I know many RPGs even hype one of their selling points as "with this game, you can emulate anything...even that!" But me? I just can't get into it.
The big problem I run into is what I call "The Imaginary Ceiling." This is the implicit understanding that, in a game taking place in a licensed property like Star Wars or Harry Potter, no matter what you and your players do, all you will ever be are guest stars in someone else's world. Even if you establish in your own fiction that every main character of the show/movie/game was murdered or never existed, or your story happens thousands of years in the past or future, you cannot escape the notion that this world only exists because someone else created it, for different characters, in a different story. A lot of people probably don't think about that, or don't care. I kinda wish I was one of them, because I do, and as a result, I'm never going to run a Fallout tabletop game, a Skyrim RPG, or a Guardians of the Galaxy Fate Core hack, as much as I love the idea of it.
Even franchises that do have their own tabletop game suffer from the Imaginary Ceiling. If you're running a campaign of, say, A Song of Ice and Fire RPG, and an epic and brutal betrayal happens in that game, then it's going to get compared to the Red Wedding. Even if it's more epic, more brutal, and more surprising than the Red Wedding, it is doomed to always live in the shadow cast by an event the actual creator of the world did.
All that said, I am able (at least a little), to get over myself and just play, occasionally. Look at my Firefly RPG campaign, for example. I've also blogged before about what a formative experience playing the West End Star Wars RPG was for me, growing up. But those games were exceptions that proved the rule. With Firefly, I was barely familiar with the series, and quickly disavowed myself of most general similarities between the show and my game. With Star Wars, most of my games were disconnected one-shots that were so far removed from the movies, they might as well have been any sci-fi setting.
And that, of course, is a defense I've heard before (and used myself, obviously): "Well, we stray so far from the source material it's really our own thing." Well, then, why isn't it? Why did you play Star Wars and throw out the characters who made the movies what they are? You can use psychic powers and "energy swords" in any sci-fi setting, right? I understand what you mean...that you basically used the source material as inspiration, a jumping-off point for your own adventures...but to me, that just feels a little like bowling a perfect game with the bumpers on. Even if the ball never hits them, there will always be an asterisk by that score.
But, I do understand that some people don't give a shit about that asterisk; they just want to have a fun game. I get that, too. I guess this is just the frustrated writer in me. I'd rather build something from scratch and borrow/steal details from other settings before actively playing in those settings and pretending I did something original. That sounds a little harsh when I put it out there like that, but the bottom line is this: I just cannot relax in someone else's world.
Now, RPG settings, written and built with RPGs in mind, are a completely different thing altogether. Those settings are just that: settings. Character-less, story-less places, waiting for you and your group to pick up and run with. I'm cool with that. I can live with that. To me, the two most important parts...the characters, and the plot...are missing, so plugging those into another setting works for me. That is inspiration I can work with. But I can't just take a franchise like Star Wars or The Lord of the Rings universe, pretend those heroes didn't exist, and pretend that this is all my idea and not in fact someone else's. Maybe it's just ego, but I think me and my players can do better than that.