Aliens Who Are Great at TV

The reason we haven't seen evidence of intelligent extraterrestrial life is that their TV shows are way to good for them to start thinking maybe watching somebody land on the moon would be a better broadcast. When you think about it, it makes us seem kind of uncreative, really. It would be more impressive if somebody had faked it.

The Problem with Non-Apocalyptic Settings

We know there's going to be an apocalypse sooner or later. You might as well put one in yourself. Those bunkers under Denver International Airport weren't built for fun.