Nothing wrong with a honest term of respect and/or good manners. It's usually possible to tell from context and tone the difference between people who have good manners and people who are being condescending, even when the words are the same.

[And I don't call my mother-in-law by her first name. I just can't do it. The woman is nearly fifty years older than me and calling her by her first name is just... wrong. Miz Kate is the closest I get. So I know what you mean about 'sir' and 'ma'am'.]