<human>: We have been dating for 1 year.

I just finished an exam and am pretty exhausted. My girlfriend and I planned to play a video game when I got home, but while we were waiting for the game to start she begins this extended recount of a movie (based on a book) that I have absolutely no interest in. She is going into detail about the characters and the plot and (may be my crappy mood) it just seems like I wouldn't have cared for this movie even if I was watching it myself. I let her go on for a while, but it becomes annoying to listen to so I begin to express my disinterest somewhat overtly. 

After it becomes clear to her that I wasn't interested, she gets all quiet. I ask her if anything is wrong and she says nothing. A bit more time goes by and the game still hasn't started so I just say a short "good night baby" and she says good night and so I say bye and hang up the phone. A couple minutes go by and she calls me back demanding to know what's upsetting me... What!?!

Can you summarize the given text in a few sentences?
<bot>: How do I express disinterest in something without offending my girlfriend? She is sensitive and several times she has gotten quiet when I have disagreed or expressed disinterest in something she is passionate about.