You can use the phrase "where I come from" to talk about differences between your home town, region, or country and the place where you are now:

Where I come from, people say "Excuse me" when they bump into you.

People usually use this phrase when they're complaining about things that people do, which are considered rude in the place that they're from. It's common for people from small towns to say things like this when they go to a big city.