# What I want to do
if ($value == 1 or $value == 5 or $value == 21 or $value == 99){...

# How I often do it:
my %list = (1 => 1, 5 => 1, 21 => 1, 99 => 1);
if ($list{$value}){...

# Wouldn't something like this be better?
if ($value IN (1, 5, 21, 99)){...