Thanks to many wonderful suggestions and thought-provoking comments from all of you, I've had some further insights.
- It's okay to hoard chocolate. Sometimes, daily survival in another culture requires that we make sacrifices. In this case, I may be sacrificing some rules of etiquette but I won't be sacrificing my sanity. Yay!
- Giving indoor shoes for a toddler who doesn't understand the difference between "indoor" and "outdoor" shoes while seemingly ridiculous to me (why bother?) feels like a step in the right direction toward engendering tolerance from my in-laws. Not one person here has pointed the finger at me and called me a bad mom, but honor and reputation are very, very prized here and I really want to keep mine untarnished for as long as possible.
- No matter how many times I think I'm starting to get the hang of things and fit in, something new will come up. Yesterday I unthinkingly used my chopsticks to take a piece of food from my husband's chopsticks in order to give it to my daughter. He gave me a "look" and sternly warned me about how inappropriate that is in Japanese culture. Thankfully, his mother, the only witness, played ignorant. (She is a wonderful woman!) In my defense, my husband was reaching across me at the table to give food to my daughter and frankly, I get tired of having his arm in my face at mealtimes (for some reason he refuses to sit on the other side of my daughter so this happens all the time). Furthermore, I was raised to believe that reaching across the dinner table, in front of others, is rude. Can you say "culture clash"??
- It's sometimes hard to know what I can or should chalk up to differences in parenting style or personality versus larger cultural issues. Living with your in-laws, even within the same country and culture, is bound to result in some discomfort and the revelation that we don't always do things the same way. However, when you add in the "gaijin" (foreigner) factor, things get trickier for me. There are times I don't want people here to think that I'm representative of my culture and that "all Americans do x". On the one hand, I'd like to show that there are different ways of doing things since a lot of Japanese culture seems to be really homogeneous - "there's the Japanese way and it's the only way". But trying to show the "American" perspective is challenging since one of the things I most love about the U.S.A. is the diversity of people and ideas. The last thing I want to convey is that my way is THE American way. Needless to say, I think about this a lot and I find that it's complicated. Perhaps after living here for a while longer, I'll find a way to let it all go and just...be. In the meantime, I struggle to figure out how to choose my battles when I'm not even sure where the lines are being drawn.