5.- No one but their creator understands their internal logic.

4.- Even your smallest mistakes are immediately committed to memory for future reference.

3.- The native language used to communicate with other computers is incomprehensible to everyone else.

2.- The message, "Bad command or filename", is about as informative as "if you don't know why I'm mad at you, then I'm certainly not going to tell you".

1.- As soon as you make a commitment to one, you find yourself spending half your paycheck on accessories for it.