Democracy and collaboration in general. I love the idea of working together with people for the greater good and the idea that if we just all have a say in things, that will make things better over time, but it feels like the last few decades have shot down both these notions. We've got our own democratic system here in the US that's getting attacked by foreign actors who are jamming up the system with misinformation, noise, and propaganda. We've got Congress members who appear to be on the take from foreign governments and don't seem to have any sort of agenda apart from gumming up the works and bringing government to a halt. I don't think a dictatorship or fascism is the solution, but holy crap do we need to sweep away the people who are obviously working in bad faith to undermine our democracy. Even just relying on people to vote in their own best interests or the best interests of the country in general is really not a reliable way to get rid of bad actors in the system.
With regards to collaboration (in business or personal settings), I've rarely seen anything come from it. In school, "collaboration" meant working on group projects where 99% of the group did nothing and 1 or 2 people drove the project forward. Much the same happens in business work groups. Trying to get friends or random strangers on the internet to collaborate on writing or gaming projects has just been an exercise in futility for years, as it usually ends up being 1 or 2 people driving things forward, and no real commitment or output from anybody else (people flake out regularly). I just stopped trying to work with other people on anything unless somebody else pulls me into something and shows some amount of progress on their end, otherwise I just feel frustrated when it seems like I'm the only one even trying to do anything. Any of my "biggest achievements" in life have been things I worked on on my own or was the primary driver behind it.