Now if you just mean why not always use the my( $a, $b, $c ) = @_; form vice shift: there's times when you want to pull off some items and then do something list-y with the remaining contents of @_. Best example off the top of my head would be something that builds a hash from key/value pairs like:

Another good example is subclassing...

sub do_something {
    my $self = shift;
    $self->SUPER::do_something( @_ );
    # do some more stuff
}
[download]