You said, "yes but I could just be a sh***y person and believe in god and pray for forgiveness boom heaven"
This is partly true. But it's important to note that saving faith is always accompanied by genuine repentance, that is, turning from one's sin to a Godly life. Jesus said,
"Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven." (Matthew 7:21)
In our day we can and do see plenty of people who call themselves Christians but live in all manner of immorality, and really don't seem to care at all for the things of God. These are the people Christ speaks of in that verse.
No, but I'll comment more on that later. People are not doomed to Hell simply for lack of acknowledging God, but for all sins that they have committed.
"But as for the cowardly, the faithless, the detestable, as for murderers, the sexually immoral, sorcerers, idolaters, and all liars, their portion will be in the lake that burns with fire and sulfur, which is the second death.” - Revelation 21:8
As for the reason I wouldn't personally condemn someone to Hell for not acknowledging me, I deserve nothing of that sort from my fellow man. God does. If I were the creator and sustainer of all creation, I would deserve such acknowledgement, but I am not, therefore I don't; and God is, therefore he does. In similar manner we would find it insulting for a child not to recognize his or her parents because it is from them that he or she has existence, like humanity derives its existence from God. Hope this helps.
