1. The writer, a Japanese girl who is describing the time when an American student came to stay with the family, has mentioned three aspects of the American girl's behaviour that she disagreed with. Then she says:
この三つは、今でも本当に悔やまれる。特に、ジュースとシャワーのことは、彼女が真の日本文化を知るための妨げになったと思う。
My translation: "I still really regret those three things [lit. those three things are still really regretted]. In particular, I think the matters of the juice and the shower became obstacles to her understanding true Japanese culture."
Is this OK? I'm not sure I have the overall tone and purpose correct. The three things previously mentioned all seem trivial, and not meriting these kind of comments.