Faith means believing and trusting in things that have no solid proof to back them up - like the safety of hot air balloons and love. The concept of faith was created because smart people poke holes in arguments, making it hard for those who need something to believe in so they don't feel so lost and stress eat.
Invoking faith is like plugging your ears and humming in the face of reality, which comes in handy when you feel like being stubborn.