I had my eureka moment when I took a job in urban MN after working on the reservation for 5 years (and growing up there before that). They announced a noon meeting and I went and they didn't serve lunch. Everyone brought a bag lunch (expect me). I was pretty ticked off and insulted[1]. I was mad the rest of the day. It took a call home and the "your not on the rez anymore" speech to open my eyes to what we hold as truths spawned from culture.
1) have a lunch meeting on a reservation on the upper great plains and not serve lunch at your peril - never mind not accepting a gift as you leave - federal rules and local traditions can conflict a bit
