I suppose the moment that most strikes me about Back to the Future is in the first few seconds after Marty travels back to 1955. The wide-open and undeveloped land on either side of the road emphasizes and signifies the thrill of this moment: power and freedom. In one moment, human genius has punctured the very walls of the universe. Marty, the benefactor, is almost God–and, better, he didn't even see it coming. The thrill of surprise apotheosis, you might call it.
But what I like most is the pristineness; that's another advantage of traveling to the past–no one could ever, ever, have seen you coming. For a moment, before your first interaction with a person, you are utterly free of responsibility.