When every ex-Muslim you meet is suddenly your bff!
When you roll your eyes when someone says "Islam is a religion of peace/love/tolerance!"
When you get an irrational urge to defend Christianity, Hinduism, and Baha'ism when talking to Muslims... ("My enemy's enemy is my friend"!)
When you participate in EDMD

When it's really hard to stop yourself from laughing when talking to a Muslim and they say something exceptionally stupid ("But if we came from monkeys, why are there still monkeys?", "See what happens when you follow science, philosophy and rationality :(" -- the last one was said to me disapprovingly very seriously.)
When you correct Muslims' grammar in Arabic just to show them they can't have a monopoly on the language
