When I was 6 and my dad brought home one of the world's first pocket
calculators, an HP-35, he tried to convince me that it had a computer inside
it. I thought that was unlikely. All the computers on Star Trek were the
size of a room and had big reel-to-reel tape recorders. I thought that there
was just a clever correlation between the keys on the keypad and the
individual elements of the LED display that happened to produce
mathematically correct results. (Hey, I was 6).

Joel Spolsky
"User Interface Design for Programmer - Chapter 2"