What's really important about gratitude? It's sharing very specifically what it is that another has done that you you're grateful for. Here's a couple of statistics, 93% of employees who reported feeling valued so that they are motivated to do their best work. 

Feeling valued comes from that gratitude from others. 88% of employees who reported feeling valued said that they are engaging in their work, and 81% of employees stated that they would be motivated to work harder if their boss expressed gratitude. 

Also think of the reverse, our boss is grateful for us, but 74% of us never expressed our gratitude to our boss. Remember, like we, these are all human relationships, and they are reciprocal.