I remember early on in my career as an electrical engineer, I went to complain to my boss about something stupid but important to me at the time. My manager looked at me and said she was busy, could I please come back tomorrow. The next day I went back to her office. She looked at me and said sweetly, "What did I tell you yesterday? I am busy right now, please come back tomorrow".
I never bothered her again and we got along wonderfully.