怀旧只是怀旧与怀人无关念旧只是念旧与旧人无关
[huái jiù zhĭ shì huái jiù yŭ huái rén wú guān niàn jiù zhĭ shì niàn jiù yŭ jiù rén wú guān]
Roughly means: 'nostalgia for objects past doesn’t equate reminiscence for people who once owned them,' it's often employed in a philosophical context regarding human emotions over memories of things and relationships.