One of my favorite goals which appears to sum up several of the more specific ones stated earlier (simple to state but not so simple to implement):

A program should always gracefully survive even the worst data.

Whether it carries on unperturbed with a warning message in a log, or dies but clearly spells out why (and does not frag the disk), will depend on the specific nature of the application. I was reminded of this today while trying to load a corrupt spreadsheet into Excel (which breaks all the rules 8-( ).

--
I'd like to be able to assign to an luser