So what is the best way to act?

I was always thinking what approach is the best.

Being distant, cold, dominant and bossylike such as giving her DIRECT orders and when shes shit testing directly telling her to watch her mouth and to behave. Mostly being serious and always direct in his intentions.

or

Being funny guy, not taking anything or anyone seriously, being able to make every her shit test into tease or joke.

I'd say having balance between the two is the best, but i would like to hear your opinions.