Opinion does not matter, there is absolute truth and that Truth is found in the Bible. The Bible clearly reveals that there is an afterlife, and that people do not disappear from existence. Every person exists on 2 realms (or "planes"): the physical and the spiritual. Because of sin, introduced into the physical world by Adam and Eve, all mankind, and animals, and all living things die. Death is simply separation from God's kingdom. Remember (if you know the story) that God said to Adam and Eve that if they would eat of the tree of the knowledge of good and evil, on that day they would surely die? They did - they were separated that day, they died, from the spiritual aspect of God's kingdom. Prior to the fall of man, the spiritual and physical parts of God's kingdom were one (heaven being God's throne, and Earth His footstool, metaphorically speaking) but the fall of man rendered him (us) unable to take part in or even see that spiritual aspect.
Mankind also, because of sin, which introduced corruption into a previously stable and perfect world, is subject to physical death, which is separation from the physical aspect of God's kingdom. This death is delayed for us only because of God's mercy - He allows us to live, even though we deserve death, because it is His wish that some would be saved. But everyone who is born into this world is essentially spiritually dead, and the spiritual death is infinitely more consequential because the soul (being the spiritual aspect of man) does not die, but is eternal and, unless it is redeemed, will spend eternity in a state of death (separation from God and His Kingdom).
This is where human religions come into play, all of them seeking to explain how man can save himself from death. But the Bible is the only Truth, the only source that acknowledges the fact that man cannot save himself, just as a physically dead man cannot raise himself up from the dead. And yet every human religion claims that if you follow some sort of prescription for righteous living, and you follow some type of outward religious code, you'll be alright. But that is utterly false - only God can save man. And the only way He has provided for salvation is through Jesus Christ, the One who He sent to die for the sins of all those who believe in Him and put their faith in Him. He is the one who overcame death and defeated it, and was the propitiation (payment) for the incomprehensibly large debt that man cannot pay on his own: sin. Anyone who tries to pay his own way into salvation is in for a rude awakening: there are only two ways the debt of sin can be paid. Either you can accept the free gift which is salvation by Jesus Christ, and go to Heaven (the gloriously restored Kingdom in the future), or you can pay it yourself for eternity in Hell, which is the outer darkness, the lake of fire outside of God's glorious Kingdom in which there will be endless"weeping and gnashing of teeth".
There is only one reason why someone would accept the latter, and that is because of pride, which is the same root sin that caused man (and Satan) to sin in the first place, and is what causes man to continue to sin today. Pride is exalting yourself, putting yourself in your imagination or mind above the reality, and all of natural mankind is guilty of it. Unless God intervenes to humble you, so that you realize your true lowly state, you cannot be saved. That is why the Beatitudes starts by saying, "Blessed are the poor in spirit, for their is the kingdom of heaven". Unless you are poor in spirit, realizing your own spiritual bankruptcy and deadness, and recognize your own sinfulness and inability to save yourself, you cannot be saved. You also have to be someone who mourns over sin, and not be someone who, in the heart/mind, says "I have not sinned", or, "I may have sinned, but at least I'm better than so-and-so", or "I'm not that bad - I don't deserve death!". You have to, after examining yourself, realize how awful sin is in your life, and cry out to God for mercy, for salvation from sin. God is a gracious and loving, and He will save all those who genuinely seek Him.
For the sake of brevity (yeah, I know - it's still kind of long) and clarity (yeah, I know - it's not as clear as it could be) I left out references, but they are available on request.