A must read book:

However imperfect society may be, we should measure it against the cruelty and deprivation of the actual past, not the harmony and affluence of an imagined future. We are fortunate enough to live in a society that more or less works, and our first priority should be not to screw it up, because human nature always leaves us teetering on the brink of barbarism. And since no one is smart enough to predict the behaviour of a single human being , let alone millions of them interacting of them interacting in a society, we should distrust any formula for changing society from the top down, because it is likely to have unintended consequences that are worse than the problems it was designed to fix. The best we can hope for are incremental changes that are continually adjusted according to feedback about the sum of their good and bad consequences