Japanese grammar as an explanation of Japanese mentality?

My Japanese is at a kindergarten level at best, but I`ve picked up enough to notice a few things.

For one, in English, we would say: "I studied textbook at my friends`s house very hard yesterday because I am bad at Japanese." The sentence structure is who-verb-what-how-where-when-why. In Japanese, 僕わ日本語が下手なので、昨日に友達の家で、熱心に本を勉強しました。(whew), which literally translates to "I, because I am bad at Japanese, on yesterday at my friend`s house, very hard I studied." The sentence structure is who-why-when-where-what-verb. Besides the subject and the verb which always fall in the very beginning and very end respectively, the order of everything in between is the reverse of English, but is often interchangeable.

But, when referring to oneself as the subject, the word "I" in the beginning is implicitly understood and often dropped. As a result, one often would never start a sentence with "I".

Might this have something to do with the group mentality--to put the group, and the individual`s relationship to the group, ahead of the individual--of most Japanese people?

I had this thought while spacing out during my 3rd period class. It was a lot more interesting and revealing then, before I put it down in digits.