1. Dark and empty? Actually, if you've ever been given a general anesthetic and awoke later having not remembered a thing about the time you were unconscious, that is the equivalent of death. Simply, nothing. It is neither dark, nor empty to you. You are just non-existent, just as you were before you were born.
2. I had religion funneled into my brain from infancy on until I could leave the nest. My parents were from a long line of Catholics and after my mother died when I was still a child, my dad remarried and converted to Lutheranism. I had to attend church regularly and attend bible school. I knew in my heart that there was no truth to it then and know the same now. I suppose you could think of it this way. If you as a Christian, know in your heart, why you do not believe in the gods of ancient Greece, Rome, Vikings, or the current gods of the Hindus, then you will know why I do not believe in your god. There really is no more evidence for the existence of their gods, than their is for your invisible, bearded being who supposedly occasionally grants wishes for people.
3. As to your last question, you want us to believe in what you believe because you were brainwashed to do this. The brainwashers were your parents, family members, parishoners and preachers. "Believe!, and get non-believers to believe!" Over and over and over, you were fed this.
That the entire universe is a complex system is true and humans when primitive had absolutely no answers at all about the universe and its wonders, so some came up with and extremely simplistic answer to things they did not understand (an invisible man did it all with the wave of his hand). It also allowed them to control the masses inner fears of death, getting them to believe in an afterlife and thus there would be no end.
Everyone wants to believe that there is no end to their existence and thus grasp onto anything that offers some alternative to an end to their lives. Believing in the existence of an invisible bearded being who will grant you immortality is a way of clinging to the idea that you won't die. One thing I can say with relative certainty and that is that while everyone says they know they will die, so far as I have seen, when each is told they are terminally-ill, they all initially go into denial. I work in a hospital with the terminally ill and their families. I've been doing this for years and they all have initially been in denial. While I am an athiest, my wife is a Christian. Many months ago, my wife was diagnosed with cancer. It is tragic to see her gradually getting worse. She is no exception to this phenomenon. When we were called into the doctor's office and informed of the diagnosis, her initial response was the same as the others....denial. Presently, she's in the depression stage and I try to keep her mentally occupied and focused on family and friends issues. So, deep down, humans give lip-service to being mortal, but in reality, subconsciously they don't believe it will happen to them and just to try and cling to an immortal existence.
Again, before you were born, you were not in the dark, alone, or scared. You simply didn't exist and when you pass on, it'll be the same. No dark. No being alone and no being scared.
Have a grand life Christian, for if you want to believe in the existence of that invisibile bearded guy in the sky who may or may not grant your wishes (prayers), that's your right. Our right is to not believe in it. But please remember this, despite what you may hear from preachers in the pulpit, we are not evil and dangerous. We have jobs and families; and we don't steal or murder. We don't preach an us against them mentality, as do preachers. We're your neighbors, coworkers, doctors, lawyers and scientists. Just regular people.