Also
Spoiler
Astrids sudden character change. the whole time she is "lets kill the emperor. It will give the Dark Brotherhood its former glory back" and a few quests later she is "yeah I betrayed you and the whole Brotherhood and got everyone including my husband killed. My bad"
Spoiler
It's the classic I thought I was doing the right thing to help but ended up screwing everyone. A common mistake made by inept leaders in ardious times.
