I hadn't thought of that angle.. those self staying up socks were too much for him to not jump into the picture
But, I will say, what a wonderful way to separate people. Those with the socks, and those without..

An easy way to check what group they belong to. Just gently pull up their pant leg a bit.. you see ankle, they are one of the unclean ones..
The waiter is smiling because there's poison in them there drinks!
"I tell ya Dan, being white, male, and affluent is freaking awesome; having socks that don't fall down makes that all the more awesome!"
Wear stay-up socks while smiling adoringly at your gay life partner and oppressing the Negro!
(He thinks they're a very sweet couple, but he wishes they'd pay him at least minimum wage.)
They probably pay better than average so he will keep their secrets and his silence; that's why he's grinning. ~_^