It kind of depends on the time of day. In the evening and on the weekends, especially after they have been drinking, Japanese people are pretty much just as loud and boisterous as anyone else. I’m not saying you should run screaming through the trains any time you feel like, but having a conversation at what would be considered a normal volume is perfectly fine in most situations.

Also, foreign ATM cards will work at any Japanese post office ATM machine and I think most 7–11s now. Though the ones in the post office might not be open in the evening.