Is it wrong to use the word boss stating your position on a name card?
In case of not being totally wrong but more of a strange character, could it in any way be interpreted as something negative, a joke or anything else than the real meaning of the word boss?
I have never seen it before as normally the word "manager" or "director" is used if in a leading position.
I would consider it a joke. A manager might want to print a few name cards with 'Boss' on them to give to friends at bars. The ones used for business should use 'Manager', etc.