Atheists are just the other side of the coin from religion, they KNOW there is no god and nothing you say matters. They can't prove it, but they have absolute faith and will fight you every step of the way because their dogma demands it.
Agnostics are more the chill ones. They know they can't prove if there is or isn't, they just know religion isn't for them.
If you have to yell that everyone else just doesn't get it. You're the one that's different.