And I didn't know Stands existed. Guess you've been relying on fancy trick shit like that too much. Don't know how to fight for real anymore.

[The "family reunion" bit gives him pause- that's not really much of a taunt- but Venkman has no reason to really believe Okuyasu means immediate family- so he digs in a little.]

Didn't mean to beat your ass in front of your ancestors. Maybe you oughta've chosen a better venue.

[It's only after he verbally kicks the guy while he's down that Venkman registers the change to Okuyasu's expression- something he is no doubt going to feel real bad about soon.]