1. No one but their creator understands their internal logic.
2. 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.
4. 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.”
5. As soon as you make a commitment to one, you find yourself spending half your paycheck on accessories for it.