The threshold of annoyance you have to inflict on your friend before he / she insinuates that you are an Indian.
This usually works on people of Pakistani origin due to the historical hostility between the two nations. Probably works the other way around as well.
Jess: Hey help me pick out an invitation card for my fiance'.
Farhan: Hahh .. another birthday? How old is he? Around 40 now?
Jess: Eeewww he's not! That would make him 17 years older than me!
Jess: Stop being an indian.
Farhan: Ooooohh .. INDIAN THRESHOLD CROSSED!!