If someone does not believe in God, would you say they are lacking in some capacity or faculty? Something is somehow holding them back?

No and yes, respectively.  Faith is mostly a willingness to find things out for ourselves.  Atheists manifestly lack this.  Rather than experience God for themselves, they move the goalposts and commit any number of other logical fallacies to avoid facing the question.

Of course, and it the application of Dan. 10:12.

Not necessarily. Many have simply not yet had the opportunity to meet Him. Thousands do meet Him and become Christians every year.

 Absolutely not though that is certainly my exact opinion of religious believers in all truth

I'm not able to pretend

hard enough to fool myself.

Is that what you are talking about?

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Regards,

John Popelish

If someone believes in God, would you say they are lacking in some capacity or faculty? Something is somehow holding them back?

Yes to both.

Gods believers pretend their perceptions are reality while missing out on the wonders of actual reality.

Some that say they don't believe in God and there are many behave better than most people that say they believe in God. 

Not all belief in God is the same.  There are different stages of religious belief, different levels of spiritual intelligence.  One person's atheism may be more intelligent, more spiritually developed, than another person's theism.

Yes, reason holds us back from sharing your factless delusions.

You know who doesn’t get impostor syndrome? Cats. Not only does every cat know they’re a cat, I think every cat believes firmly, with conviction, that they are the best possible cat, the prime example of a cat, the most cat a cat could be. Not that cats are capable of this degree of higher thought, but if they WERE, a cat would never ask, “Is this action something a REAL cat would do?” They would simply know, “I am a real cat and I am doing this action, therefore it IS something a real cat would do.”