Is your username/password correct?

Useless, absurd, must, need, appalled, just, infuriating, essential, etc. - Signal vs. Noise (by 37signals):

Is your username/password correct?
Customer: my file uploads are failing and the error says that my username/password are invalid! What's wrong?
37signals: Is your username/password correct?
Customer: Oh, no it's not. Thanks!