Dumb as a rock

The key was stuck in and my only hope to enter my place tonight was to call an emergency locksmith.
They came relatively quickly. Two guys. One giving orders, the other running back to the truck to get all the tools.
We exchange few words and they ask me where I'm from. One of the two was also born and raised in France. His parents were boat people. Then, they all came here. America after Paris. There is no track of France in the few words he says. He gets quiet and watches as his co-worker works and takes the lock apart in a matter of seconds. His hands move as if in a Rubik's cube competition. Flawless and precise dance. "How long have you been doing this?", I inquire fascinated by the motion of his hands. "21 years". He is dressed in a T-shirt with a baseball cap put backward. I am surprised. "You don't even look 21!" He stops, takes off his cap and shows me some white hair. "See? This is what I mean. Believe me I am older than I look. Not like him!" He gestures toward the French-Vietnamese guy who has been just silent since his French words. "You Asians don't age like us. You prick!". Both laugh. They're friends not co-workers. We start talking about life, girlfriends in general and more precisely, the French ex-girlfriend of the Vietnamese-French-American guy.
"A sweet girl" says his friend who has resumed to work on the lock "but dumb as a rock!". Her ex-boyfriend offers no denial.
"I thought you guys liked "sweet but dumb" girls" I joke weakly. "Well, to have fun yes, but not in a serious relationship". The answer is spoken sternly as if they had thought about this a lot. "You want to be able to discuss things, more than just hair and nail polish". Both laugh.