You weren't an idiot. You could very clearly see something was bothering Baku. Although finding out what that thing was would probably be like trying to pry a diamond out of its ore.

He was just sat there, he wasn't busy with anything, and it was very clear that his mind was running a million miles per hour. His eye was locked onto nothing in particular and his foot was bouncing up and down.

He had one of his hands up by his face, his thumb nail between his teeth, while his other hand was besides him, gripping the arm rest as if it personally wronged him in some way.

Maybe it'd do him good to go and ask what was up with him.