Top 5 things never to say in response to "How are you?" from your girlfriend's father :

5 - "I'd be feeling a lot better if I had remembered to pull out."
4 - "Pretty good, for someone in the late-stages of syphillis."
3 - "Better than you, you fat old waste of skin."
2 - "Great! I finally got accepted into the Hell's Angels!"
And the number 1 thing never to say in response to "How are you?" from your girlfriend's father :
"Huh? Sorry, I wasn't listening. I'm still basking in the image of your daughter finally doing bukkake."