Toolic already gave you the right answer.

But you might be interested in another approach using hash-slices, which is way faster for big data.

use strict;
use warnings;


my @got      = qw(blue_shirt hat jacket preserver );   # sunscreen);
my @required = qw(preserver sunscreen water_bottle jacket);

# ---------- directly coded

my %required;
@required{@required}=@required;
delete  @required{@got};

warn "Skipper is missing: ", values %required; 


# ---------- or alternative as custom function

warn "Skipper is missing: ", array_minus(@got,@required);  

sub array_minus (\@\@) {
    my ( $got, $required ) = @_;
    my %required;
    @required{@required}=@required;
    delete  @required{@got};
    return values %required; 
}
[download]

Skipper is missing: water_bottle    sunscreen at d:/exp/hash_diff.pl l
+ine 14.
Skipper is missing: sunscreen    water_bottle at d:/exp/hash_diff.pl l
+ine 28.
[download]

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