Alright, he can't help it. Joker starts to laugh, hand curling halfway up to his mouth as if he gave a passing thought of hiding it a little weight. "Oh," he snickers, shoulders shaking, "I was just thinkin' away from sight, not completely silent, but I see where yer mind went!"

Even if it is completely true that Strange sucks at shutting up, which is half of what makes it so funny to him.