I always find that the night before or right before I have a session with T, I have no idea what to say (even though in between sessions there are tons of things which I wish to discuss).
I walk in and I think that I have no idea what I am going to say or sometimes how we are going to fill in the time that the session goes for.
I always walk away thinking that we talked about some great things (sometimes things that make me feel better, others more confused - I guess that is the process of therapy).
So anyways I was just thinking that most of the time, T knows what to say and how to get to that point, even if I don't know that that is where I ended up.
Original Post
Love your name. Welcome to the forum!
But I would just add, that even when I go in "knowing" what I want to talk about...for example, if I'm organized enough to bring notes that I wrote down earlier in the week when all the ideas were coming to me...very often we STILL end up talking about something totally different. My T is very psychodynamic and relational, so she really likes to find out how I'm feeling "right then". And even though it very often starts out not looking anything like what I "thought" I wanted to talk about, in the end, I usually end up feeling like we really did get to the heart of that (or sometimes, another) matter...even though, like you said, I have no idea how we got there...and it usually feels "good" that we did that, although sometimes it is confusing...or maybe "surprising" is a better word. 
