Service is slow. Everyone wants a complex order. But it is an opportunity to socialize. Their legs and feet suggest that there many conversations and interactions going on as they wait. Perhaps the person on the right has reached the counter and is placing an order.
Note the napkin, with a lipstick imprint, on the floor. It is placed carefully to draw the eye to the foreground. While the only hand in view, is in counterbalance.
We were sitting at a table near the waiting line.