It's easy to belittle the Pharisee who congratulated himself on not being a sinner. But this Pharisee sincerely believed his words. His religion was all outward with no heart change. He didn't know that he was a hypocrite.
This is why it's easy not only to belittle the Pharisee, but to be the Pharisee–and not even know it. One common way this happens today is believing that God views me as a saint while I continue to sin every day. Learn the tell-tale signs of a Pharisee, plus how to change if you are one.