People are miserable and cynic because they are fed information that feeds into that idea. I believe it's partly the media's fault as that's where most people get their information on current events from and they don't exists to deliver you the news, they exist to deliver outrage and pieces of information that will either feed into your own biases, make you really angry or both.
This does not happen because private media is evil, or some other nonsense, but because they're companies whose survival depends on people being interested in what they're saying and paying to hear more of it. Same applies for state run media as the ones they need to satisfy are the government who pays them and they only allow things they want other people to hear to be published.
Do you want to hear some good news to lift up your day?
We currently have many systems capable of erasing the Pacific garbage patch within a decade. And guess what people want to see it done and get invested in it a it has huge potential to bring them profit so nobody has a real interest in bringing it down like it happened with some inventions in the past.
The most powerful weapon you can have in real life is not a gun, nor is it an airplane or even nukes, it's a damn camera and an internet connection/TV that is uncensored. People's opinions are shaped by what we hear, and the ones that we trust to tell us the important things will always sell us narratives and worst of it all is that this is not a political issue, as all sides of the political spectrum do the same thing, because they need to do it in order to survive. Good news don't sell, telling people that statistically the entire world is better and better each year does not sell, showing people the good that happens in their community is worse than not covering anything as it loses the media companies money if they do it too often.
You want people to be happier and realize just how good their life is/can be if they work for it? Remove all censorship, give everyone cameras and an internet connection and let them speak and see how beautiful the world is.
All this world wide unrest is born out of censorship, and the people abusing it and us for their own agenda.
A person's voice is their greatest weapon and the large institutions in all countries have been turning it against the people while doing their best to silence ours. No wonder people are depressed and cynical when the only thing they've been told is just emotional attacks after emotional attacks.