岁月不堪回首往事不再回头
[suì yuè bù kān huí shŏu wăng shì bù zài huí tóu]
Years Gone By Cannot Be Rewound, Past Affairs Do Not Look Back: A deep feeling about the irreversibility of time and past events which should not linger in memories. Maybe the owner feels nostalgic but knows it is pointless or even painful to recall those past days, so they look ahead instead.