Good Job
Being appreciated is an extremely important thing to feel, as mentioned above.
Furthermore, when you’re working at a company, or otherwise performing a function that requires you to, essentially, serve another person, it’s an incredible feeling to be told that you’re doing a good job. It takes appreciation one step further and specifically indicates that this person is doing or providing something valuable and appreciated. These small words will have a big impact on your partner, your parents, and your clients/employees, if applicable.