I think you missed the point of this advice. Stepping out of your comfort zone is designed to allow you to grow as a person, not make you be something you are not.

If you are so introverted that you can't possibly go to an event without making a complete fool out of yourself (a real fool, not just what you think is foolish) you've got a serious issue that is going to put you at a disadvantage in many areas of your life.

There's a huge gap between having faults, recognizing them, accepting them and overcoming them when you choose to and being perfect in every way.

I don't see how completely ignoring your weak points and pretending they aren't relevant to you makes you a better person, however.