Employee Appreciation Day is an unofficial holiday in The United Kingdom, The United States, and Canada. This day is set to motivate the employees by thanking them for their services. The psychological reason behind setting it up was to improve boss and employee relationship in the work environment. These appreciations via messages, sending images on WhatsApp or giving them a gift works as a glue.
You can send these Quotes to your subordinates too, it is to support them. Every manager or higher rank post official can send to lower rank one.
Studies suggests that such activities perform on regular basis of randomly and even yearly improves the job satisfaction, adds more energy, motivates them to work even harder and better.