Depends on my mood. Generally as soon as I open my mouth that is considered an open invitation to ask about where I came from, why I emigrated, etc. even worse from Brits because they tend to feel some kind of kinship with me and think I will talk their ear off all evening. I just got done with 6 hours of flying, 3 hours sitting at airports, I'm supposed to be asleep already, I just want some food, a beer and go to bed. It is easier to stifle the conversation right now than look for awkward excuses later.