For me it's Urban Zakapa's "I don't love you" (t/n: with Eng lyrics :D)
Last time, I finished school and took the bus with my earphones on, I cried rivers while listening to this songㅋㅋㅋㅋㅋㅋㅋㅋ
There were 2 people sitting next to me were looking at me and they looked like university students, one unnie handed me a kleenex, I've kinda got used to it but I still cry when I listen to this songㅋㅋㅋㅋㅋㅋㅋ
"I don't love you, though you must know it too" Those lyrics just pierce my heartㅠㅠㅠㅠㅠ
You must listen to it, what song makes you cry?