When I was a teenager, I went through this brief phase where instead of saying "dad", I used his first name. Not intentionally, it was just wires getting crossed in my brain, but he would get so pissed about it.

Don't recall ever calling my mom by her first name. She wouldn't appreciate that either... in fact, it bothered her that I said "mother" instead of "mom" for the longest time (we had a strained relationship, so the more formal term felt more appropriate).

On the other hand, my parents never required me to say "sir" or "ma'm".