Leadership's Secret Sauce
Saying 'thank you' and appreciating people for their efforts is the secret sauce of leadership.
Without a doubt in my mind, I can say from personal experience, that expressing appreciation and praise develops deeper relationships, fosters collaboration & connections, and helps you stand out as a leader. Thanking someone genuinely for the work they do says, "I see you, I notice what you do and I value you." It leaves people with a positive feeling and people usually remember the way someone made them feel.
Showing gratitude and thanks at work isn't about developing a friendship. It's about you developing professional leadership skills.

As a leader, genuinely praising people is a simple yet powerful strategy that you want to master.
According to Stone & Heen (2015) appreciation is fundamentally about relationship and human connection. At a literal level it says, "thanks." But appreciation also conveys, "I see you," "I know how hard you've been working," and "You matter to me."
They go on to say that when people complain that they don't get enough feedback at work, they often mean that they wonder whether anyone notices or cares how hard they're working. They want appreciation.
Be Genuine & Be Specific
Deliver praise from the heart - be sincere
It needs to be viewed as authentic by the recipient
Deliver praise as soon as possible - seize the opportunity to amplify the joy
Make praise specific - a simple thank you is not praise; it is politeness. People need to know exactly what you valued in their effort
Praise doesn't always need to be verbal; an email, a post it note or a card with a thank you message can be well received
Recognise the little things as these are often the acts that make the workplace function effectively
For recognition and appreciation to be valuable it needs to be regular, and in the language most important to the team member.
It is most effective when it is about them personally
An example might be; Thank you for the time and energy you invested in our project. It was a polished performance due to the effort you put in to it. The feedback was so positive. You are a valued member of our team.
As leaders we want to be actively looking for things our people are achieving that further the values and goals of the organisation.