Amy: Okay, listen to me. I love working with you, but you have to understand how scary this is for me.
Sheldon: Why?
Amy: Because I don't want to get lost in this relationship. And when you pulled me off my project, it seemed like my biggest fear was coming true, the-the things that are mine are getting subsumed into the things that are ours.
Sheldon: I wouldn't want that to happen, either. Thank you for explaining, and for using the word "subsume," that's one you don't hear enough.