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 file name," 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.
In the interest of gender equality ...
5. They're heavily dependent on external tools and equipment.
4. They periodically cut you off right when you think you've established a network connection.
3. They'll usually do what you ask them to do, but they won't do more than they have to and they won't think of it on their own.
2. They're typically obsolete within five years and need to be traded in for a new model. Some users, however, feel they've already got so much invested in the darn thing that they're compelled to remain with an underpowered system.
1. They get hot when you turn them on, and that's the only time you have their attention.