Interesting experiment from a 18 years old student from Chicago, testing people reaction when they are called beautiful front of the camera.
The topic is not new, but certainly provides a nice fresh angel, there is also the famous small movie on the this topic called the Validation
Positive feedback is a simple and great tool, somehow underused in very many retail interactions, I think this is a real gem, it can be customised to so many situations! Just to have here a simple example: when you are buying a new cook book the shop clerk instead of saying thank you for your shopping, he can say to you WOW you must be an awesome cook! That´s a big difference, think about it and use it next time you design your target customer journey!