So, as far as the cross is concerned, I think there are many layered meanings. It is deep and profound .
Don't think of God unilaterally deciding to sacrifice his son as part of some vindictive punishment. Remember Jesus is part of the Godhead and willingly laid down his life for us.
Someone quoted upthread "The wages of sin is death but the free gift of God is eternal life"
Death has been ordained by God as the outcome of sin. It is a logical consequence if you like of not doing things the way God would like. It isn't so much about physical death ( although we do die physically) but spiritual death. Inability to commune and connect with God when we marr his creation in us.
If you think about it, God can't just ignore sin because it is so often the way in which people get hurt. We demand justice when people do something evil in our eyes. I don't think we would really want God to actually ignore wrongdoing (especially when it hurts us, or those we love.) God is just.
However he is also loving. Willingly, in Christ, he took on our death wages in his death. He bore it for us and when he rose from the dead he gifted us his resurrection life instead.
I also think that on the cross Jesus (God) entered into all of our suffering as humans. He showed himself as willing to experience undeserved deep pain and suffering as we sometimes experience too. He is not some God in heaven, remote and indifferent to what we go through, but God with us ( Emmanuel).
The Bible also talks about Christ conquering death. What is the ultimate finality for us has been defeated and something new and liberating and eternal has been given to us in it's stead.
As far as heaven and hell is concerned. This is something I'm still thinking quite hard about. However the New Testament talks about us being refined as by fire and that all that is made of wood and straw and rubble will be "burned away" and that which cannot be burned, gold and silver and precious stones will remain.
So I don't think you need to worry about the douchiness of people in heaven as their (and yours and my) douchiness will have been refined and gloriously only that in them/us which is created by God and is part of his design in them will remain and shine to his glory. Unlike another poster though, I don't think we lose our individual identity in heaven. God has made us individual as well as corporate and I think that stays.