Buenos Aires has impressive waiters

How?  From the Guardian article:

"Typical Buenos Aires senior waiters memorise all orders from clients and take the orders, without written support, of as many as 10 persons per table. They also deliver the order to each and every one of the customers who ordered it without asking or checking."

And most of the time, they get it right.

The trick:

Interviewed afterwards, waiters said they generally paid attention to customers' locations, faces and clothing. They also disclosed a tiny trick of the trade. They "did not pay attention to any customer after taking a table's order, as if they were protecting the memory formation in the path from the table to the bartender or kitchen."

In preparing their study, Bekinschtein, Cardozo and Manes discovered a published account of a remarkable waiter who had trained himself to "recall as many as 20 dinner orders, categorise the food (meat or starch) and link it to the location in the table. He also used acronyms and words to encode salad dressing, and visualised cooking temperature for each customer's meat and linked it to the position on the table."

Go read the whole article.  It's very interesting.