Are they afraid to go deeper because they don't want to become targets of those who disagree so they always skate on top of pleasant and quiet so they don't make waves or cause undue attention? There are some topics they will never discuss because they are fraught with emotion and strong views and that can get very scary hairy. So they STIFLE IT. Is that the life you are living? Being satisfied with just the tip o the iceberg and never going deeper because of fear or lack of interest? What other reasons do some people have for never letting you see their entirety vis a vis what they really think and feel about life?
