To me personally, it’s when the speaker clearly has no interest in the topic but still talks about it anyway for some reason (meetings, presentations etc.). In all honesty, I could listen to people who talk about a topic they’re passionate about for literal hours even if I don’t understand anything they say, but as soon as someone drones on about something they don’t actually like in a “I’m expected to say this so just get this over with” kind of way, my brain shuts off - even if it’s a topic I would normally enjoy hearing about.