Some people are spring-loaded toward hostility. I remember probably around 25 years ago before iphones and ipads, I saw the United captain of my flight out front when we were both waiting for rides. I called out to him "thanks for 9" and he looked like he was going to punch me in the face. I said "uh um sorry thank you for activating channel 9, I know you don't have to and some of us really enjoy listening" and he totally relaxed and said "oh you're welcome." I always wonder what he thought I meant.