They're rarely helpful. Actually, they usually add insult to injury. But what would computing be without 'em? Herewith, a tribute to a baker's dozen of the best (or is that worst?).

"To err is human, but to really foul things up you need a computer.” So goes an old quip attributed to Paul Ehrlich. He was right. One of the defining things about computers is that they–or, more specifically, the people who program them–get so many things so very wrong. Hence the need for error messages, which have been around nearly as long as computers themselves..

In theory, error messages should be painful at worst and boring at best. They tend to be cryptic; they rarely offer an apology even when one is due; they like to provide useless information like hexadecimal numbers and to withhold facts that would be useful, like plain-English explanations of how to right want went wrong. In multiple ways, most of them represent technology at its most irritating. //

13. Abort, Retry, Fail? (MS-DOS)
    In many ways, it remains an error message to judge other error messages by. It’s terse. (Three words.) It’s confusing. //

[UPDATE: Almost four hundred people have chimed into this discussion, and many nominated other error messages that are at least as worthy of celebration as the ones in the story. So celebrate ’em we did–please check out The 13 Other Greatest Error Messages of All Time.]