Originally Posted by goru
It's just good manners. Nothing to do with being an US citizen.
May be it is not a US thing but a Christian (church goers) manner nevertheless. We do not follow that.
No, it is not a good manner. Why would it be? Where it is written? By the way, why does it bother you if some don't take off cap? May be their hair is all messed up after a long day.