The various levels of "Fuck off" I employ:
"Fuck off, [gender]" = half joking.
"Fuck off." = dismissive
"Fuck off!!!" = Angry
"Fuck off, [name]!" = If not in a setting in which I must specificy which being needs to fuck off, it's an expression of deep personal disappointment in you.
Fuck off, [species]!" = You have irritated me to the extent that your entire branch of the animal kingdom needs to fuck off!!