I watched the first 2 episodes of the Hidamari Sketch x365 Specials with Xillball, as well as the first episode of the main series again by accident (I opened the wrong folder). I was nice being reminded how much the animation improved from season 1.
This was really the start of Studio Shaft's distinctive style.
Despite being side content, the specials contained a lot of hints at characters and events that are coming in the next season.