I think, often, because 'religion' is such a PERSONAL issue to many, its not only HARD to talk about it, possibly because of the contraversy around the subject, but often, when we DO, people think that we're trying to shove our beliefs down their throats!
As far as the prayer thing goes...often, we have our eyes CLOSED to pray where its harder to LOOK someone directly in the eye and voice our beliefs....
Just sayin...