When Roger laughs, he essentially admits that he was wrong about the damper—which seems like a big step for him. Both Roger and Julia can then tell the other that they don’t have to feel so insecure in their lives and relationships. After getting to know the other’s spouses, they can both see how in love the other couple is. And hearing this from a stranger is enough to bring both Roger and Julia to tears, though they blame it on the smoke.