Trying to set my appointment

I'm a little disappointed. So I was told by my Dr that I can tell the office to squeeze me in whenever is convenient for me. So as I tried to reschedule today a snappy old lady asked me not so politely-"why". Um, why do you think? Because maybe the 16th doesn't work for me? And told me the 16th will be fine  for my appointment. Are you kidding me?