I don't know if this is really an unpopular opinion but the more I think about it, which is often, the more it makes my head spin. I don't think you should necessarily do what makes you happy especially if you can help your society, even though it is inevitable that no matter what we do, at some point, humanity will die out and the Earth will cease do exist.
To elaborate on this, say you become a surgeon, a very good surgeon and you have dedicated your life to getting good grades, going to medical school, the whole bit. After some time you realize you don't love what you do and you want to pursue your passion of, whatever the psyduck. Even if you are miserable, you are doing good for the community and I am of the mindset that the needs of the many outweigh the needs of the few and you should feel obligated to live a miserable existence if you are able to better the lives of many.
I also think we should cherish life and do what we can to save people and extend their lives even though we are overpopulating the planet, which is tough because that will eventually lead to a decrease in quality of life for everyone, especially since we are all living longer and will keep living longer. The other part of me thinks that once you are dead, and even alive, none of it matters anyway so just do what makes you happy while you can which is a complete paradox to my previous paragraph but I believe both simultaneously?
The more I think about it the more pointless it all seems, and it is, pointless. Let's even say that... Christians are the one religion to get it right and there is a heaven! Sounds great right? Spend eternity in bliss. So what is eternity? Until the end of time? How do you quantify that? Time is a concept of humans, how do you spend eternity in bliss? It never ends? How? Honestly, the thought of infinite nothingness sounds more appealing to me than losing my mind in a never ending, never changing "eternity". At least, in my perception of death, once you die, there is nothing, you don't experience anything, which doesn't seem possible and is making my anxiety spike even typing this but at least when it happens I won't have these worries anymore.