守不住的笑话留不住的笑话
[shŏu bù zhù de xiào huà liú bù zhù de xiào huà]
Translates as 'A joke that can't be held on to is a fleeting one.' Expresses a sigh at how some jokes don't have long-lasting power and may be outdated very quickly, or it might suggest a more abstract idea, about how we can hardly hold on to any happiness or smile forever. It conveys some kind of philosophical thought or sadness in the ephemerality of joy.