It always nags at me a little (just a little) that they are not more careful using ideas, references, and even objects that would have had to evolve in an exact parallel as it did on Earth to end up being exactly the same as we do things here. Not just casual things like a helmet or a pistol shooting bullets but there are some points where I would have though the writers would change it up at least a little bit. One example that immediately comes to mind is that their idea of government is exactly the same as ours. They have a congress, vice president, and they even call their leader the President. They have lawyers, trials, even "Freedom of the Press". Their military command structure is exactly the same, they have the same separation of Military and Civilian leadership, and so on. How did they manage to evolve all of these ideas to reach the exact same conclusion as we did? If you watched the show and they never mentioned where they came from or where they were going you'd never even question that they might not be from Earth.
It seems a bit lazy on the part of the writers, but on the other hand, I guess it lets them get on with the plot and not have to explain a bunch of mundane details.