Experiences imprint and mold each person. Some have vastly different experiences throughout life as the person next to them, which doesn't mean the ones with less experiences are soulless- they just haven't had the opportunity to test themselves or been put through the fires of life and tested or purified.

Also, fear plays a huge part in the way people are. Usually the fearful- (and ALL fear stems from fear of death), are the ones who seem soulless.

As C.S. Lewis said, "You don't have a soul, you are a soul. You have a body."

Just my 2 cents.