My instructor was my sensei and yes I called him that. He helped to guide me not only in the martial arts but also in some other parts of my life. I thought of him as a friend, instructor, and someone I could go to with questions beyond the martial area.
I have never allowed, nor will I my students to call me sensei. Fist off i teach a primarily Filipino system not a Japanese or okinawian one, secondly to me there will only be one sensei in the system I came up in at that was my instructor.
Now I have seen many new black belts put a label on their uniforms that says SENSEI and watched them strut around like they have accomplished something. To me this has always seemed wrong as they have not earned the right to be called SENSEI yet. After years of training students if the students call them sensei thats fine but I do not feel the title, name, recognition comes just by becoming a black belt
and don't even get me started on those that call themselves JR SENSEI