There are no correct answers, only complementary oppositions. People always argue one side of the coin, but forget that the coin wouldn't exist without the other side. To clarify, they are both part of a greater whole. One cannot define black without white, male without female, happiness without sadness. Understanding one means that there needs to be an opposite to define it by. Therefore they are interdependent and need each other to exist.
Things get trickier with the mention of God and the advancements of technology. Heaven and Hell, life and death, and reality itself. This is where logic can be used to deduce a thoughtful response - just falsify it. Taken from Wikipedia (since it sounds more eloquent than myself), falsifiability is the logical possibility that an assertion can be shown false by an observation or a physical experiment. That something is "falsifiable" does not mean it is false; rather, that if it is false, then this can be shown by observation or experiment. A religious person may believe God exists and a quantum physicist may claim that there are infinite realities existing at the same time. Both cannot be falsified, therefore both cannot be proven false (or true for that matter).
From an evolutionary standpoint, humans evolved from apes, most closely related to chimpanzees and bonobos. Chimps are known to be violent and aggressive, while bonobos alleviate tension in groups by showing love or by having sex. Humans have seemingly adapted both traits and are capable of both altruistic behavior and violent wars. People have always theorized and thought ideologically about how to improve humanity. Wishing for world peace or eternal happiness are both wonderful ideas, but due to many variables these are unlikely to happen. In the end, morality itself is a man-made invention.
We can only define happiness because we know what sadness is. To get rid of sadness would be to get rid of happiness as well. If this is true, then one should embrace sadness in order to experience happiness. You can relate this to any emotion or experience you've ever had. So the best option in life is to do what you believe in and let others do the same, because you aren't right or wrong, just different. In the words of Nietzsche: You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist.