[darkengine]

The exact example you mentioned (a person's weight being taboo) was my first "culture shock" when learning Japanese. My mind was opened to the multitude of prejudices carried just by speaking English many times after that.

At one point I kept a Twitter account where I tweeted random thoughts about the world only in Japanese. Even though it hardly had any followers, there was something really freeing about this. It forced me to choose my words precisely (lacking a deep abstract vocabulary, it required careful perusal of the Japanese dictionary), and I also didn't feel subject to the cultural burdens of English (as for the burdens of Japanese, I wasn't yet aware of what they were). I definitely recommend to language learners keeping a little diary in their second language, once they get to a point where they are able to.