お疲れ様 (おつかれさま) might be the ultimate “get used to it” phrase. I hear it all the time these days – when anyone returns to the office from an outing we say it to them, I say it to everyone before I leave work, I say it to the guy who empties the trash, I say it to someone if they are leaving.
I’ve started saying it a lot more than I used to, partly because I hear it so much. I did hear it in Nishiaizu, too – when I paid my bills, after I got back from elementary school, when I left school – but it gets used a lot more now.
I guess it literally means something like “You look tired,” but a more accurate translation is, “Thank you for your efforts,” which I learned from Kitakata Alan. That effectively expresses the idea that it is a set phrase used when someone completes something. If you look at the times when it is said, it is generally at the point where one activity ends and another begins. You can emphasize this by making it past tense – お疲れさまでした. If, on the other hand, people are still working (i.e. the activity has not reached completion), then you can say お疲れさまです.
Perhaps the best, most ritualized example of this is at elementary school. The kids all do the cleaning themselves after lunch. Sixth graders run groups of kids from all grade levels. All the groups line up and begin cleaning by collectively yelling, お願いします. They end the cleaning by saying, ご苦労様（くろうさま）でした, which is just a more casual way of saying お疲れさまでした. I would always air on the side of お疲れさま, since it is more formal.
Try not to think of the meaning too much. Focus on the situation when it is being said and then try to notice when a similar occasion arises, so that you can use it. And say it a lot, just kind of throw it out there sometimes.