I kind of liked the idea of putting in the mood of the programmer in comments.

# code to mimic uniq(1)
[download]

# mode: divine
my @result = do {
  my %counter;
  grep ++$counter{$_} == 2, @input;
};
[download]

# mode: tired
for (@input) {
  $multiples{$_}++;
}
for keys( %multiples ) { 
  print "$_\n" if (--$multiples{$_});
}
[download]

(And yes, both example stolen from Get All Duplicated Elements in an Array (Once, without shifting), and I mean absolutly nothing with the different modes.)
And when refactoring this code, a mode that suggest that the programmer was tired, drunk or thought him-/herself being merlyn is prime candidates for a rewrite.