It's mock aggression in the sense that when people laugh they're often teasing, kidding around.

我们知道打闹是装出来的，因为人一笑,我们就知道他们是闹着玩的。

耶鲁公开课 - 心理学导论课程节选

They say it, so that we don't have to and we laugh our heads off.

他们说出来了，我们就不用说了，我们只管笑掉大牙。

街上的售票员 - SpeakingMax英语口语达人