An average looking young nobody and a few confederates who explain to onlookers that he is "Thomas Elliott" and was either in The Hunger Games or will be in a Spider-Man movie make the day of various young women at a mall. The video isn't really that amazing — the title cards rather overplay it. But, yeah ...
Much of the job of being a celebrity is mustering up the energy to make your fans' day. Taylor Swift is famous for this. It looks easy to do on your own schedule, but could you do it all the time on the public's incessant schedules? John F. Kennedy Jr. apparently figured out at some point that his main talent and thus his calling in life was Making People's Day (or, considering the dynastic psycho-energies random people invested in him, Making People's Week). He became a gracious figure to all the people he rode in elevators with as he went about his business in NYC, which helps explain some of the bizarre media outpouring when he died in a plane crash in 1999. In New York media circles, everybody had at least one friend who had once met JFK Jr. and he'd been like a prince to them.
One interesting converse of this is that talented actors can use their acting skills to go about their daily business unnoticed and live like normal people when they feel like it. For example, my wife and I were at the crowded L.A. Auto Show in 2001, looking at some zillion dollar car, and she asked me a technical question about it to which I had no idea what the answer was. The lady standing next to her chimed in and explained to us the engine was a V16 and so forth and so on. When she walked away after a couple of minutes of technical conversation, my wife said, "That was Tom Hanks' wife."
So, I started looking around for Hanks, who was at that point still about the biggest movie star in the world. And sure enough, there was Tom Hanks nearby, wandering around like everybody else, looking at exotic cars that, out of the thousands of people all around him, only he could afford. No bodyguard or personal assistant. He had a baseball cap pulled down low, but he's tall enough to stand out in a crowd, except that he'd set his body language and facial expression so that he'd look completely uninteresting. It was like that Jedi mind control scene in Star Wars: "This is not the Forrest Gump / astronaut Jim Lovell / Capt. John H. Miller / Woody the Talking Cowboy Toy you're looking for." I watched dozens of people walk by him, with only a few doing doubletakes after they'd passed him by and realized, "Hey, that nobody looked just like Tom Hanks, if only Tom Hanks weren't Tom Hanks!"
There's a famous story about Marilyn Monroe and a friend walking down the street in New York City unnoticed, when the star stops and announces she's now going to switch from Normal Jean mode to Marilyn mode. With minutes, traffic is gridlocked.