I've known many people to do just the opposite. They respond with a negative comment or disagree with everything I say. It drives me crazy. I don't know if they are trying to impress me with how critcal their thinking is or if they are trying to foster a debate. Whatever they are doing I don't even want to contine to talk to them. Agree with me if you agree, disagree or discuss an issue if you legitimately have a valid point or just say nothiing. It works for me.