If a software program was to be released without any bugs.....there'd be no subsequent sales of updated, "bug-fixed" software. (*cue omenous music*) Maybe I'm paranoid, and obviously nothing is ever perfect, but I rather suspect the inclusion of deliberate bugs (ahem, features) in some cases. Sort of the equivalent of planned obsolescence.

__________________________________________________________
It is hard to convey five-dimensional ideas in a language evolved to scream defiance at the monkeys in the next tree. -- The Science of Discworld III: Darwin's Watch, by Terry Pratchett, Ian Stewart & Jack Cohen