忘了过去薄了青春
[wàng le guò qù bó le qīng chūn]
'Forget The Past And Waste Youth' implies giving up some past memories (good ones) due to certain changes in current circumstances or personal beliefs. The word 'Waste Youth' refers to a period full of dreams and vitality not being lived fully because it is too obsessed with memories or regrets from the old days. This shows nostalgia over past experiences but also a hint of sadness or self-blame.