回忆是条疯狗
[huí yì shì tiáo fēng gŏu]
This metaphor compares 'recollections of the past' (whether they're sweet, bitter, sad, etc.) to a crazy dog - chaotic, unpredictable and hard to control or calm down. Such thoughts about past experiences sometimes can disturb a person's inner peace just like a mad dog, showing the complicated feelings about certain painful or crazy memories.