A pretty common logic error is forgetting to explicitly check all expected values against the variable: 
use strict;
use warnings;

my $foo = 'boo';
if ($foo eq 'goo' || 'moo') {
    print "$foo\n";
}

[download]

when this is really desired: 

if ($foo eq 'goo' || $foo eq 'moo') {

[download]

Obviously, this is not unique to Perl, but I do see it quite often.

In reply to Re: Little annoying mistakes ... of others by toolic
in thread Little annoying mistakes ... of others by szabgab

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