不知不觉放不下不痛不痒忘不掉
[bù zhī bù jué fàng bù xià bù tòng bù yăng wàng bù diào]
'Involuntarily Can't Put Down Something Unmemorable But Also Indelible'. This conveys the complicated sentiment towards something unremarkable yet still unforgettable, hinting at subtle longing or reminiscence.