Definitely 1 Litre of Tears, I ran out of tissues while watching this drama, and I cried 3-4 times in each episode T_T <3 So amazing and yet the sadest thing ever.
Definitely Bu Bu Jing Xin. It has 35 episodes and I started crying somewhere around ep. 26 and did not stop until the end. I ended up with one of the worst headaches of my life. It was too interesting to just drop it but now I know I will never rewatch it because I am not that masochistic. Brrr