I sit here in a Starbucks, having been awake for about 24 hours, sipping coffee to keep going. An image on Twitter reminded me of how vast the universe actually is, not difficult for a scientific person to grasp, the notion that we are a tiny speck, inside a tiny speck, inside another tiny speck, of a tiny speck, of dust in this vast cosmos.
The sad fact is that no religious person truly grasps the concept of forever, much less infinite in any amount. Even Einstein, a deist, was hard pressed to comprehend it, thus why he was afraid of things like quantum physics.
It is easy to see how little they grasp about the concept of infinity, as they talk about "forever" as casually as if they are talking about tomorrow. This limited view keeps them from facing the most scary notion to a planet bound organism, that we float endlessly for all eternity through an infinite vast emptiness.
It also protects then from fearing their own myth, by not comprehending the notion of infinity, the "after life" becomes nothing more than a pleasant weekend getaway, instead of the truly horrific monotonous form of torture that it would actually be. Consider the vastness of the universe, and living as long as it would take to get from one side to the opposite if the universe stopped expanding today, using current space travel technology and an infinite source of energy.
Less than one percent of the way through the voyage you would have read every book ever written to date, including all alternatives, and all languages they have been printed in. Yes, you would even actually finish War and Peace, and every word of every scientific paper published and unpublished.
After two percent of the trip you'd have done every scientific test in the scientific papers you read, and verified them with several repeated tests. You would have the scientific understanding of a god at this point, nothing would be a mystery to you because of our inherent ability of inference.
Now we're just nearing the fourth or fifth galaxy of this trip, at three percent. Your tops scores on every video game ever written would be perfect, impossible for anyone to score higher. You would have ever race track memorized, every glitch mastered, ever combination perfected, every letter of every script known.
Any psychologically healthy human would have been insane three fold at this point, and there is still 97% of the universe left. You would have lived a thousand lifetimes just to get to the next galaxy, eaten more than a billion tons of food.
Food would literally be tasteless after only a few hundred years of thus trip, your taste buds would be unable to distinguish one flavor from the next out, because the repetition would would eventually cause the neurons in your brain to be flatlined in sensory input, all valences would be neutral.
Hallucinations, a combination of memory and imagination, would haunt you after only five hundred years because of the monotony. This is less than a hundredth of a percent of your trip too.
Adding more people to the trip would increase the degradation of sanity, after a few hundred years everyone would be paranoid of each other with violent consequences. This is not because of a biological flaw.
There's the catch, religious people will likely claim it's a biological flaw in our brain or body that would be removed after death, but this is not an effect of biology. The boredom is an effect of memory.
Unique memories always stand out to us, because they are easy to identify in the crowd. When no memories stand out we begin to lose focus, we call this phenomenon boredom.
The progressive insanity and delusion is an effect of logic, once all that is possible is known to a single logic center, it will make up new things to explore because curiosity is an inherent trait of logic, the need to explore. Religion seeks to destroy the curiosity, which always results in psychological instability because the logic engine of the intellect becomes damaged.
This can cause many things, almost always the loss of curiosity results in hallucinations of various degrees. You often hear religious people describing a relatively mundane event as "spiritual," even mentioning voices or visions.
These are hallucinations cause by logic methods being imbalanced. Much like a painter with only three colors, the picture is incomplete because there us no curiosity asking the important questions, so the gaps are filled in with random nonsense.