Once when I bought Serana home to her Father, I was thinking my idiot vampire hunting character was probably looking at the bodies on the tables being fed on by vampires and having second thoughts as to the wisdom of taking a vampire home to her vampire filled lair so she stayed on the balcony and watch the reunion from there. I thought Harkon would walk up to me when he got to the point where he wanted to talk to me, but instead he said in this level tone: "I am not known for my patience." Needless to say, I was off that balcony and in the centre of that hall with Harkon quicker than you can say Fus Ro Dah. Next time I tried to make him say that again, but he chose something different and outright threatened me, along the lines of: "It is only for Serana's sake you aren't already dead. Now get down here." So I always lurk on that balcony now to see what he'll say to get me down this time.
I recently discovered that when you go to beg the Jarl's aid for Riverwood after the destruction of Helgen it is possible to avoid Irileth, talk to the Jarl directly and have a completely different initial conversation with him. Surprised the hell out of me when I discovered that as I'd been playing Skyrim two years.