A person who is religious has the following symptoms, being religious is a mental disorder that varies from almost unnoticeable to extremely religious:
A strange incapability of using logic to find things out.
A brainwashed attitude, absolutely refusing to hear anything against said religion.
A tendency to barely even think for themselves, preferring to use said religion instead to steer them through life, this trait in particular is so annoying that they hardly even socialize with people not belonging to said religion
A bond with fellow religious people that is so strong, they'd vote people like George Bush
to president because he belongs to their religion even though he's a dumbfuck
A (varyingly strong) lean towards right wing politics.
And lastly an urge to spread their religion to other people.