It may actually be a control issue for you but there's another way I can picture it, too. Suppose when you walk into a session you're still juggling a whole lot of bits and pieces in your head, not sure how/if they'll turn out to fit together or which one to start looking at first. You'd probably prefer to begin at the beginning, but which part is the beginning? If you started in some places you might have to do a lot of backtracking, have a harder time pulling the story together, and maybe get left with a lot of loose ends. You and your T would be doing a delicate dance, encouraging you to go for it and get all it out, but also not to be afraid to back up and start over if necessary the better to get it all out.

I figure that creative control in saying your say isn't necessarily a bad thing.