I'd likely be a bit more sarcastic in person once I got to know you. Outside of my Mennonite Brethren home is a culture that uses dry, teasing and self depreciation as a means of expressing friendship. Everyone had a nickname and if you were accepted it meant you were teased. To be left alone was a sign that you didn't fit in.
I recognize this is a Minnesota thing or perhaps better, it's an indigenous peoples culture that has been adopted into a greater group. I also recognize that many people perceive it wrong.
Another cultural tendency is to recognize a wrong action or tendency and to point it out rather than stay silent. You stay silent with an outsider, not with a person you consider a friend.