I believe that the rain represents the rough, cold reality of life. Basically, the man/boy doesn't understand that life is tough and will involve challenges. Meanwhile, the girl is aware of them, yet makes the effort to stay optimistic in spite of them.
"...Nothing's changed because you can't stop the falling of the rain."
Within this line, Billy is pointing out that there will always be challenges in life, and you can't control whether there will or wont be. However, what you can control is the way you handle them. You can either live life like the man/boy by simply ignoring/running away from the hardships of life, or you can live like the girl, who stayed happy even though she faced challenges.
I believe that the rain represents the rough, cold reality of life. Basically, the man/boy doesn't understand that life is tough and will involve challenges. Meanwhile, the girl is aware of them, yet makes the effort to stay optimistic in spite of them.
"...Nothing's changed because you can't stop the falling of the rain."
Within this line, Billy is pointing out that there will always be challenges in life, and you can't control whether there will or wont be. However, what you can control is the way you handle them. You can either live life like the man/boy by simply ignoring/running away from the hardships of life, or you can live like the girl, who stayed happy even though she faced challenges.