>>794482Not to be a smug atheist but it really does all come down to chemicals. Your life is about manipulating your brain to release the right chemicals to make you feel good. And some people really struggle to release those chemicals because their brains are wired differently or because they're in an environment that causes the brain to not want to release the chemicals. Oftentimes they use shortcuts like alcohol and drugs to get the happy chemicals but suffer long-term side effects that leave them worse off than before.
Consistently the best way to generate the happy chemicals is to have a good sleep pattern (sleep at night for around 8 hours and wake up in the morning), socialize with others on a regular basis, be in a physically intimate romantic relationship, have societal obligations to incentivize you to get up in the morning, have a good work life balance, get enough sunlight and vitamin D, exercise several times a week, eat a balanced diet that includes some fruits and vegetables, and have plans for the future that are reasonably achievable. Almost no one is able to do all of those things consistently, especially not under capitalism, hence all the unhappiness. But really sleep is the big one. It's crazy how much it impacts your mood.