Yu-Gi-Oh is the result of Serial Experiments Lain

Okay, so... in the final episodes of Lain, Lain basically re-writes reality to one where her best friend can be happy.

Now, there's a lot of messed up stuff involving computers (among other things) in Lain, not to mention ancient conspiracies and possibly magical powers.

Let's assume that Lain's friend isn't capable of dealing with that stuff normally, and doesn't have the brains or knack or just plain doesn't "get" normal self-defense forms like Martial Arts or guns (she probably can't get guns in Japan anyway), but for some reason really loves CC Gs.

So what does Lain do? She creates a world where all the monsters and magical shit and ancient conspiracies can have their asses kicked by playing a holographic/pseudomagical card game. Lain's friend is all set!

... Just something I came up with while in the car.

Makes perfect sense!

Don't be ridiculous. We all know that Digimon Tamers is the result of Serial Experiments Lain.