(Best depicted in the movie "The Prestige", which I highly recommend). This reaction is a natural responses to looming, unfamiliar power. Understanding this sort of thinking is especially useful for an interesting thought experiment:
Imagine yourself a common man of the 19th century.
In your mind, the word "electricity" produces a few fascinating, but rather vague images of white lighting, flashing fantastically and creating a magical ambiance. This dangerous force is rumored to miraculously resurrect life, and its extraordinary power could best the grand innovations of your time, such as the use of coal and oil. But this is all you know, and these thoughts rarely enter your mind... Electricity remains a part of the beyond.
Now imagine yourself in your brick home, late at night, writing a letter by the fireplace. Outside the window, you can see a single carriage being heftily pulled down a stone path by a large horse. A man sits in the driver's box, next to the yellow glow of an oil lamp. You ink your pen and worry that your letter won't arrive at its destination in time, as you try and judge the distance and time it will take for your letter to reach the next county.
As you wonder, your thoughts disconnect and repeat and you feel yourself being lulled to sleep. Awareness escapes you, and then...
Fear strikes you like sudden siren and before you can breathe, you are jolted with the shocking tremor of a lightning bolt. You feel the pull of gravity, and your legs impulsively brace themselves. As you realize you are now standing, the thick rush of mechanical engines, blinding lights, and the crushing rush of wind assault your senses.
You're in an intersection, and the year is 2010.
Consider now your mental state for this visit to the future. Being well acquainted with the busy intersections of 21st century, it's very easy for us to retroject our understanding onto the certainly overwhelmed mind of the 19th century man, to better understand his perplexing situation.
Here's a stimulating thought:
Think of every electronic device you have plugged into an outlet right now... How would you explain this, in detail, to the 19th century man?