First, I can understand Shen's loneliness. Shen is a special child. There is a big birthmark on his face, which has a great influence on him. So he has been very lonely, living in his own world. Said he could feel Shen's feelings for many times. Many times, she is lonely, but.
Second, what happened to Shen resonated with him. On the road to fame, G.E.M. also worked very hard. She suffered a lot of grievances and was not understood. That feeling is very uncomfortable. Therefore, when Shen used music to express his inner grievances, loneliness and inferiority, he thought of his own experience and the kind of discomfort when he faced grievances. Therefore, she will cry.
Third, Shen's personal experience is very distressing. The birthmark on Shen's face brought him great pain. When he was young, he was laughed at a lot. Such a child is very distressing. When he told his past, it was really distressing to see the sadness on his face.