I hate with a passion people agreeing with you just to cut conversations short.
Why don't you like them agreeing with you?
The other person does not seem to be fully engaged when talking with you.
People who are not fully engaged in a conversation is frustrating and annoying. If you notice them flippantly agreeing with you in the future, calmly point out their behavior and try to bring them back into the conversation with their full focus.
Bullshit. I'm sick of people being like this.
I'm just saying that if you call them out on their behavior then maybe they will stop doing it.