Applies to any employee
If you need another reason not to be a Karen, here it is. If you show the slightest shred of human decency and appreciation to a worker, they’ll likely want to go the extra mile to ensure that they maintain your image of them. Employees are thriving for attention and appreciation, and if they don’t get it from their bosses, you as a customer should give it to them.
This is simple human resource management stuff, to be honest. If you’ve read a textbook on the subject matter, you’ll learn that workers don’t just work for money. They want to be patted on the back for a job well done, and they’ll continue to do a good job if they receive recognition for it.