You may know the Japanese word sumimasen, which generally corresponds to “excuse me” and is one of the more useful phrases to learn, but like most aspects of Japan there’s a little more to it than appears on the surface. First and foremost, sumimasen (soo-mee-mah-SEN) is used in any situation where you need to apologize for something small, such as causing someone inconvenience by bumping into them in the street, calling the wrong number, or ordering curry with beef intestines accidentally because you couldn’t read the kanji in the menu, then asking for something else instead. Many situations which would call for a “thank you” in English work better with sumimasen in Japanese, something I learned at a public bath a few weeks after first arriving here. We’d stayed a few minutes after closing time, causing minor inconvenience to the staff who no doubt wanted to get home, and as we left my Japanese coworker said sumimasen to them (“we’re sorry for taking too long in the bath”) rather than the phrase I would have used, arigato (“thank you for letting us stay a few minutes past closing time”). When I asked about this, I was told that “‘Thank you’ sounds cheap. ‘Excuse me’ is a better word for Japanese people.” The sumimasen phrase is also used when asking for service in a restaurant, and one difference between Japan and the U.S. is that in Japan, it’s okay to loudly use the phrase to indicate that you’re ready to order, whereas in the States you usually close your menu and sit quietly to be noticed most of the time. Like many Japanese phrases, you can use the all-purpose word domo (which loosely means “very”) to add a layer of politeness, e.g. domo sumimasen! (“I’m really sorry!”).
Sumimasen is one of the most commonly used words in Japan.