Life, liberty, and the pursuit of happiness. When I first learned about the US constitution, I thought the pursuit of happiness was an odd choice there. What did that have to do with government. Certainly the government shouldn't kill people, and certainly it shouldn't deprive them of freedom, but the pursuit of happiness is an internal thing. How could a government have anything to do with that?
I've been reading a history of peri-enlightenment France called "Passionate Minds" recently. It argues that the pursuit of happiness is actually the most subversive of the three unalienable rights. Turns out that monarchies often take their power as a divine gift. In that case, common people are spiritually bound to work for the monarch. Working for yourself is just an affront to god.
Many people in Christendom seem to have viewed life as a suffer-fest that they worked at so that they could get to heaven. Even if they thought they could improve their life, it wouldn't have seemed acceptable to try. Making the pursuit of happiness a right is directly contradicting much church doctrine of the time.