Most people like to be recognized. But what if the person who spots you in a crowd is not another person, but rather a computer?
Facial recognition technology has come a long way in recent years and has never been more of a threat to your privacy.
"It's very good," Pinellas County Sheriff Bob Gualtieri said.
The Pinellas County Sheriff's Office operates one of most sophisticated facial recognition programs in the nation. Computer software measures facial features, like the distance between eyes, depth of sockets, width of the nose and dozens of other data points to find a match.
"The deputy could take the person's photograph, upload it into a laptop and run it against the facial database, which is known images," explained Gualtieri.
The deputy must seek permission to take a person's picture and run it against a database, and Gualtieri says there are strict limits.
"To use it for purposes other than law enforcement, I think it's a problem," he said.
But that's exactly how some facial recognition is now being used across the country.
"Everybody may have their information put into a facial recognition database, whether you want it or not," says Stephen Pearson, managing partner at the High Tech Crime Institute in Largo.
Pearson teaches law enforcement and military special ops about new technology and potential security threats. Universal facial recognition worries him.
"Facebook has one of the largest facial databases in the world. What they want to be able to do is, when I take a picture, recognize my face, his face, her face, and pull up their Facebook profiles. And say, 'Do you want to add these people?' But what they are really doing is opening up huge security holes for people who don't want to be in facial recognition."
Soon, facial recognition will be used not to keep us safe, but rather to target us to advertisers. The technology is coming to the grocery store, in the form of "smart shelves."
The devices, which are still in development, will rely on hi-tech sensors to identify the facial features of shoppers and predict their sex and age to offer real time coupons for products they might be interested in buying.
"Why not have ads and other messages for things that you are interested in?" asked University of Tampa marketing professor Erika Matulich.
Overseas, the giant British retailer Tesco just announced it is installing facial recognition screens at more than 400 gas stations.
"We're running so fast into this world of technology, we're not looking at what we're opening ourselves up to," Pearson added.
Because today, a picture is certainly worth a lot more than just a thousand words.