Their military and civic branches are labeled with the terms Hostility and Harmony, which says a lot about their dual personality. The new Advent race are perhaps my favorite race so far, mostly because they have such an interesting attitude and aesthetic.
Others for maxing out fleet capacity, gifting huge amounts of cash, or finding all the artifacts will net you a nice little mention on the achievements page. Others, like Fear of Icebergs, require you to win a game without using any capital ships at all, and will require a more focused effort on the part of the player. Frigate Killers simply ask you to eliminate 1000 frigates, which is bound to happen eventually.
We look at them as ways to identify and also challenge your own gameplay style.
There are literally dozens of these so getting them all will be a mighty task for even the most die-hard Sins fan. The developers have also added some cool new touches, like game-specific achievements.