人生若只初相见当时只道是寻常
[rén shēng ruò zhĭ chū xiāng jiàn dāng shí zhĭ dào shì xún cháng]
This poetic expression comes from Chinese literature. It conveys melancholy at how meeting someone initially seems mundane but over time turns into profound affection or loss, with regret for missed cues at first meeting.