croak "WTF? You gave me a nested array for the type of '$name'?!?" ...
croak "Can't grok type specifier '$type' for member '$name'";
[download]

Please, please, please do not be glib or flippant or obscure when you're phrasing diagnostic messages. Diagnostic messages are where you should put on your best interpersonal and technical communication skills.

(The best diagnostics say what the program was trying to do, where in the code it was trying to do it, what the program got, and what the program was expecting. That's all.)

To a lesser degree, comments in the code should also be informative without being too informal. Your code is a mode of your personal expression, and a few well-placed mutterings about your thoughts may guide the reader, but if the tone sounds too informal, it can get in the way of a useful code review or bug hunt.

This is a personal preference, but one which is tempered by having to work with source code from many authors over a long career with many people with different personalities and from many different cultures.