If you don't know what the subroutine does, then maybe you shouldn't be calling it! The context is all important, and there is a difference between returning an array and returning a list when used in scalar context. Consider:

use strict;  
use warnings; 

sub mysuba {
    my @fred = qw(The quick brown fox);
    return @fred
}

sub mysubb {
    return qw(The quick brown fox)
}

my $resa = mysuba();
print "$resa\n";

my $resb = mysubb();
print "$resb\n";
[download]

Gives:

4
fox
[download]

So you do have to be careful of context, and what the subroutine returns.

(There are many other party tricks you can play with this - which just goes to show the kind of parties I get invited to).