You know you're white, but do you think about it all the time? Probably not. But at times where it makes a difference (i.e., when you're the only white person on a bus), at that moment you're aware of the fact that you're white. I don't know, it's hard to explain.
Islam? I don't know enough about it to pretend to be able to answer that. Not every muslim is a violent terrorist, of course. My only guess is that right now, Islam is being used and perverted by warlords and dictators in the Middle East to make people do extreme things. Kind of like how Christianity has been used over the centuries by different leaders to make people kill or go to war (Crusades, Spanish Inquisition, witch hunts, etc)