The Aeneid, which is the first book I really struggled with in a long, long time, and I didn't even enjoy it. That may be because I had to read it in two days due to the nature of my course. But still, most of the "villains" are women!
Not being able to refrain from sarcasm, cynicism, or snide comments for more than 2 1/2 hours. The plan was for my roommate and I to be "sweet" for 12 hours in a row. She only succeeded because she didn't have class today and hasn't seen anyone. I now have to literally remain silent until 3:00 this morning.