Serana never seems to shut up when standing close to me... If I for example is chopping some wood or make some potions she usually ends up very close to me and repeats "Yes. What did you need?" over and over again, until I either become mentally ill and need to go to a hospital, stop doing what I do in order to silence her, or install a mod that practially makes everyone silent unless I bump in to them.
Well, she is a woman, thats realism for you!

And be thankful that you cant marry her, because after marriage that line would change to something like "Why did I marry you, you useless piece of junk?".