I have to believe that most people would say yes if God asked them to do something. But the catch is, God usually gives people the opportunity to say yes once he sees them live a yes.
Living a yes is a life of faith, of discomfort. Living a yes requires not making decisions based on my comfort, but God's will. Moses lived a life of yes, and was asked to lead the slaves out of captivity. David lived a yes and was asked to slay Goliath. Paul lived a yes and was asked to be a missionary. Jesus lived a life of yes, and redeemed humanity.
That means living a yes for God's glory. See Isaiah's response to God in Isaiah 6.
People who live a yes have bigger lives, optimistic outlooks, and accomplished dreams.
Are you living a yes?