This quote means that humor is really important to the speaker. It’s like a protective layer that helps them to stay strong and cope with difficult moments in life. Humor gives the person the ability to deal with their problems without the problems getting them down. It’s just like a Teflon coating that you add to a pan to keep food from sticking; the problems won’t be able to “stick” or bring the person down. Humor gives the person a shield of faith that can help protect them against hard times.