I'll offer some thoughts I have on the matters you brought up and you can take it for what it's worth.
Originally posted by: E equals MC2
"Isn't it bit presumptuous to say those worldly people who seem happy are really not happy deep inside because they don't know Your God? There are plenty of people I observe who ARE truly happy without believing in Your Christian God"
Having been on both sides of the fence (agnostic for the first 19yrs of my life and now Christian) I would have to say that the difference in my happiness is readily apparent. Most of my good friends who don't actively pursue their spirituality seem less happy to me than my friends who do. I have seen this in a general sense. Speaking specifically of Christianity, your faith will come into play here. To truly find happiness and peace here on earth and in the life to come a person must be able to answer three essential questions: 1) where did I come from, 2) what is my purpose in being here, and 3) where am I going after this life. If you're Christian, then you believe that Christianity holds the answers to those questions.
That's not to say that all people who profess Christianity are happy nor that all people who aren't Christians don't have a measure of happiness in their lives. These are just the observations I have made with the people I have come into contact with.
"You mean to tell me the hundreds of thousands who die in the world EVERYDAY that don't believe in Christ all go to hell? Why is it their fault that they weren't even given the opportunity to at least hear of Christian God? Please don't give me the [God works in mysterious ways] line."
My church differs from most Christian churches in this regard. I don't believe a just God would condemn His children to hell just because of the place they were born in and the opportunities to hear the Gospel that they've had. What loving parent would do that??
I believe that people who have died without a knowledge of the Gospel will be given an opportunity to learn it in the next step after death. Missionaries will teach them and they will have the opportunity to reject or accept what they are taught.
I also don't believe in the traditional concept of hell (another place my church breaks from the others). I believe that there are different levels in the afterlife. Everyone will go to that place which they have been judged worthy of. To think that all non-Christians are doomed to suffer in fiery flames for eternity seems absurd to me.
"If Adam and Eve sinned. Why are WE paying for their sins? Who came up with such system and why does it have to be that way? Why did God had to send his one and only Son to atone for our sins (John 3:16)? That seems awfully man-made logic to me. If God is truly almighty, why is he bound to such silly & restricting tit-for-tat system?"
I guess it depends on how you think we are paying for Adam and Eve's sin. I believe that Adam and Eve made a very hard choice. They could have stayed in the Garden of Eden and lived forever but they never would have known the joys of parenthood. They needed (as well as the whole human family) needed to be given the chance to choose good or evil and determine if we would be worthy to return to God's presence. While in Eden, Adam and Eve didn't have that choice, they were innocent and would remain so until they had a chance to choose. That ability to choose right from wrong came about because of their sin and subsequent expulsion from Eden.
I am personally grateful for Adam and Eve's choice because it has given me an opportunity to prove whether I will obey or whether I will not. That choice needs to be made if want the opportunity to return to God's presence.
If you believe in justice then you must believe that there are laws we must follow and consequences when we break them. Would it be just for God to allow His children to enter into Heaven when they had transgressed His law? Because we will all do things that are wrong in life there needed to be a way to reconcile this. The only way was for God to send His perfect Son to atone for what we did. It was the only way in which the demands of justice and the demands of mercy could be satisfied.
Let me try an analogy that might better illustrate this. Suppose a man borrowed money from another man and promised to pay him. If he doesn't pay back the money he will go to prison. Suppose the first man spent the money and didn't work very hard to earn the money to pay the person back. The debt collector comes and asks for his money. The debtor admits that he cannot pay the money back and to please have mercy on him. For justice to be satisfied the debt collector must receive his money. To do otherwise would be unfair to him. The debtor, while guilty, pleads for mercy so that he doesn't have to go to prison. How can both mercy and justice be served here?
Now suppose that a friend of the debtor hears of his friend's plight and decides that he will pay his debt for him. This man has the means to satisfy both justice and mercy and does so, willing to sacrifice for his friend. This is the same may that the Savior paid for our transgressions. He was the only one capable of it because he was the Son of God and perfect.
In regards to your question about God being bound to that system, of course God is bound. God is bound to the laws of the Gospel in much the same way we are. If God tries to break those laws than God would cease to be a righteous being and God will never cease to be such.
"Why does God have to damn those to hell? Eternal damnation... isn't that pretty harsh? For what, not loving you back? If God is truly love, which is what Christian God profeses to be, then why do the creation have to accept him back in order for us to deserve the creator's love? Can he not abolish hell? Is He helpless?"
I agree that eternal damnation sounds very harsh. Like I said above, I don't believe that God would mete out an unrighteous punishment. If you believe that God is truly a loving Parent, than you must believe that He will do what is right and merciful. Will we have to pay for those things we have done wrong? Of course, that's what happens when you break the rules.
Regarding God's love, we don't need to accept Him in order for us to earn His love. He loves all of His children, even those who disobey Him in the worst ways possible. That doesn't mean there won't be consequences to our actions though. Just think of your own kids (if you have them). You still love your children even when they fill the kitchen with flour or break your new 50" TV. There will be consequences to their actions but you still love them.
Regarding God abolishing hell, it goes along with what I said above. There has to be some kind of punishment for transgression. If not there would be no law, no order, no consequences, and no righteousness. Can you imagine how the world would be if there were no consequences to our actions? No laws to obey? We would live in anarchy and chaos because people would just do whatever they pleased and the biggest and strongest would subjugate everyone else. There must be laws for us to have order and justice. God is the same way.